The Republicans under Eisenhower, and pretty much until Nixon's Southern Strategy, supported social programs, civil rights, fighting income inequality, investments in infrastructure, education, etc. Even under Nixon, they still supported a Basic Income.
Since Reagan, the Republican Party has moved very far to the right, focused primarily on lowering taxes for the rich, undermining the social programs they used to support, creative gerrymandering, and suppressing votes they don't like (often black votes).
Under Reagan there was still some sanity and reason behind it and especially under George HW Bush, but since Newt Gingrich, the party seems to have abandoned all common sense, embraced lies to justify war under Bush jr, and with Trump, it's just all lies for the sake of lies, with every remaining principle they used to have thrown out of the window, with the lone exception of power for its own sake, and hurting people they disagree with.
McCain and Romney seem(ed) to be the last of the old guard that still care (somewhat?) about basic honesty.
Though I guess the move towards the current insanity has nothing to do with anything resembling conservatism or "right" anymore. But the party has definitely changed beyond recognition. And I do think it started with Nixon's Southern Strategy, which was already about sacrificing principles for power. The first step on a very long slide down.