I know it is a bit ridiculous to ponder "what if Trump, but good" and I don't mean that precisely, but the basic truth is that every Republican president has the weight of the news media behind them and all they have to do is not fuck *everything* up. Simple path to being very popular.
They can do horrible Republican things - even horrible Trump things - as long as they show enough restraint to not break absolutely everything.
None of them managed.
Yes Saint Reagan won re-election in a landslide, but he wasn't a very popular president (nor very unpopular, mostly) except for the real Americans in the Beltway who worshipped him. Over the years we've had a lot of dishonest coverage referring to the fact that he left office as a very popular president, but that is based on his lame duck polling which tapped into some sympathetic nostalgia for the senile old bastard.
Clinton versus the Gipper.