"Oh those RINOs and NEO-CONS won't do anything... we have to purge the party of these spineless unprincipled traitors"
It's kinda funny... I generally find most who use the terms neo-con or RINO, except ironically or as a joke, to be unable to define either in a meaningful way.
Much as George Orwell wrote about the term "fascism" in "Politics and the English Language", for almost everyone using the terms, "RINO" and "NEO-CON", are just signifiers for "things and people I don't like".
Thing is... The only current Republican members of congress (both house and senate) who can fairly be called "RINO", are Susan Collins, Lisa Murkowski, Brian Fitzpatrick, Chris Smith, John Katko, and Jeff VanDrew (who actually was a democrat until last year).
Everyone else, is absolutely within the "normal spread" of positions for Republicans... That includes Ben Sasse, Pat Toomey, Fred Upton, Mitt Romney, Liz Cheney, and most of the other congresscritters (not on the RINO list above) that voted to impeach Trump.
In fact, several of those that voted for impeachment, are notably far MORE conservative than Trump... The first couple I mentioned above have lifetime ratings over 90% from the American conservative union, and almost always vote with the party (they're available online from acuratings dot conservative dot org /acu-federal-legislative-ratings/ )
The first major mistake many make, is in thinking that loyalty to, or agreement with, Donald Trump; is any kind of criteria for being a Republican, or a conservative... Since Trump was and is, neither of those things. Trump is an ACTUAL Republican in name only, and always has been... He was officially a democrat, until he needed to be a Republican, at which point he officially signed up to be a republican... but he never actually changed anything other than the initial beside his name.
The second, and fundamental mistake however, is in thinking the republican party is actually conservative, or in fact has EVER been conservative, by any meaningful definition of the term (except perhaps, relative to the actual left).
The Republican party is, and since reconstruction mostly has been, a moderate centrist party about MOST things... Generally averse to change and risk, and generally collegial in reality, regardless of the rhetoric fed to the base for fundraising purposes.
Even Reagan wasn't ACTUALLY conservative... He talked a good game, but in reality, he was as much a "neo-con" as Bill Kristol.
Barry Goldwater was the closest thing to an actual conservative in the post war Republican party... and he was really more libertarian than conservative by modern sensibilities (though he of course considered himself to be conservative, and was mostly thought of as such in his time). Before Goldwater, you need to go back to Coolidge to get an actual conservative.... and before that... Ummm...
.... Yeah... Look at the history... The Republican party is NOT conservative, and never really has been.
Historically speaking, post reconstruction, the majority of the republican party, has been in the mold of Bush the elder, Nelson Rockefeller, Gerald Ford, Richard Nixon, Dwight Eisenhower, and Herbert Hoover... RELATIVELY conservative compared to "progressive" leftists in the democratic party, they're still for Big Government, just not AS big as Democrats. They're still just as paternalist as Dems, only about different things in different ways. They're in favor of plenty of control, intervention, and regulation, on both social and economic issues... because everyone has their "special" cases, and those "special pleadings" add up.
Reagan was a near literal revolution in the party, and he wasn't even actually that conservative... He was RHETORICALLY conservative, but in fact he governed as what most who identify as "conservative" today (who, mostly, are very definitely NOT conservative in any meaningful way), would call a RINO... Or if they actually knew what the term means, pretty close to a neo-con. He was a free spending, massive debt accumulating, heavily interventionist in domestic affairs, heavily interventionist in foreign affairs, massively intrusive, NON-conservative; by anything like a reasonable definition of the term. He just TALKED about being otherwise... and how that was better.
... Which it IS... but he didn't even try to actually govern that way...
In fact, the Reagan administration and Republican congressional leadership, essentially made what some might consider a "corrupt bargain" with the Democratic senate majority leader Robert Byrd (for the first and last years of his term... the Republicans had a narrow senate majority for 6 of Reagans 8 years) and Democratic speaker of the house during his presidency Tip O'neil (all but the last few months anyway); wherein the Republicans got most of THEIR spending priorities passed through congress and signed by the president, and in exchange, so did the Democrats... and both knew that was happening, so they were able to freely posture, to raise money off "fighting for their constituency", while in reality, there was always a deal to be made.
Which ACTUALLY meant that the government was doing FAR MORE than it had ever done since WW2... And not coincidentally SPENDING far more than it had since WW2, and accumulating FAR MORE DEBT than it had since WW2.
The fact is, Goldwater and Coolidge were major outliers, and exceptions to the general run of Republican candidates and presidents... and were largely unpopular within the party because of it.
For that matter, Reagan was also unpopular within the party, until he placated the southern religious social conservatives after his brokered convention loss in '76 (which happened in the first place, because he offended said southern religious social conservatives, in an attempt to gain broad centrist appeal, by selecting a more liberal Republican running mate, and saying a few things the leaders of that block didn't care for... Had he not pissed off the southern faction of the leadership, Reagan would have won the nomination in '76... but probably lost the presidency).
The social conservatives have never actually been a majority in the party... Only a plurality... A little less than 40% at peak... but they're a very LOUD plurality minority... and those opposed to them are very LOUD too, about how big and bad the social conservatives are; making them seem like they were and are much more powerful and consequential than they actually are... or for that matter, much more conservative, and much more principled and consistent than they actually are.
... But every national candidate in the Republican party has to make the southern religious social conservatives at least tolerate them, because said southern social conservatives have enough power and mass to BLOCK someone. They can't actually MAKE the king... as I said, they're less than 40%... but they can keep someone from being crowned, and no other single block is able to do so, because no other single block is more than about 25% of the party... Nor is any other single block motivated and organized enough to do so.
But that doesn't make the party actually conservative, or actually socially conservative, at the national level (local is an entirely different story... State and local level politics are a totally different beast).
One other thing the party has very firmly NOT been, along with "actually conservative" is POPULIST... In fact, they've GENERALLY been rather the opposite, at least when it comes to national and international issues and policies (local is a different matter entirely).
Until Trump that is...
Or at least the Republican party hasn't been populist since the FIRST Roosevelt... who was VERY firmly a populist progressive (Hoover wasn't a populist by nature, but he took some seemingly populist... and quite harmful... actions based on some truly epically bad advice from his cabinet and congressional caucus)...
Actually, TR would have been a quite "progressive" democrat in the post WW2 period up through the late 60s or so, and he had a disturbing tendency towards fascism (seems to have run in the family).
Hell... TR could easily have been LBJ, or his cousin Franklin...
...He wanted strong social safety nets set up and paid for by government, with socialized pensions and healthcare. He was for strong protectionist tariffs and strongly against free trade. He was pro-union and anti-corporation to a shocking degree, and he was pro-government regulation of almost everything. Read "The New Nationalism", and it's like postwar democrats fantasy platform...
...except that TR was personally moral and ethical, unlike the thoroughly unethical, amoral, and frankly evil, racist rapist that LBJ was.
So... if you're an actual conservative or libertarian or "conservatarian", guess what... YOU are the one who is a Republican in name only.
If you're one of those who is using RINO as an insult to describe Republican party members who aren't at all conservative, you've got the perspective reversed, because THEY ARE THE PARTY; not the conservatives and libertarians, who generally VOTE republican, because they are less awful than the realistic alternatives.
... If you think about what the party actually is, as opposed to what you think it SHOULD BE... Well... RINO... isn't an insult, or at least it shouldn't be. It's kinda like that line "Your boos mean nothing, I've seen what makes you cheer".