Run as a moderate. Trump in 2016 ran on $1 Trillion infrastructure deals, middle eastern dovishness, apathy on SSM and preserving entitlements while keeping conservatives happy with things like originalist judges, anti gun control, cutting regulations and limiting legal and illegal immigration. Trump in 2020 ran a campaign much more like a traditional Republican, decrying socialism against the neoliberal Joe Biden. I believe if Trump governed closer to his 2016 campaign (and the GOP congress didn't oppose it) then he would have been in a better position for re-election.
This implies that Trump's base noticed (or cared) that he didn't follow through on his policy promises. I don't think there's much evidence for that.
Take two concentric circles. Divide them by any number, lets say four for this argument.
The people inside the inner ring of any quadrant is the base. The people in the outer ring is the potential swing voters or other side's voters you can peel off in that specific quadrant. Its like the crust on the pizza, Trump didn't get passed the cheese to the crust, the crust is what gets you over the top.
The people who don't care are the people in that inner ring, the people in the outer ring are the ones Trump could have obtained but didn't in some alternative scenario.
Throwing numbers out again, above what Trump got:
69% with NCW, 55% with CEWs, 40% with Hispanics, 20% with Blacks, 40% with Asians.
Its important in these discussions to not lose sight of just who exactly we are talking about at any given point.