The party will only change if Trump gets destroyed. But that's not going to happen. If he actually loses to Harris, he will cry that the election was stolen again and his supporters will do the same rebellious shyt they did in 2020 and 2021. Republicans in Congress won't do shyt because they are physically scared of Trump voters. The ones who try to change the party back to somewhat of a sane party will get the death threats and smoke from Trump world (the pundits and supporters in the media, social media, Trump himself, etc)
If Trump doesn't run in 2028, the election will be about who can be "Trump without the baggage". Ron DeSantis will try to fill this role. And you'll have a few other Governors and Senators that will run and try to be that. Nikki Haley will try to run as the sensible person again but the party is too sexist to make a woman the nominee and she won't be seen as crazy/MAGA/authoritarian enough.
I think it takes 1 more election cycle to truly wipe out this MAGA shyt, but if Harris somehow beats Trump, I don't see her being a 2 term President.