I can see Democrats been favoured in the House until 2032 (when the 2030 cencus kicks in) and the Senate until 2036 (Tester is not up in another Presidential year until 2036 and the GOP needs his seat to offset future loses).
But if Trump wins by 5 I don't think Democrats would do any better than 2018 in the House, but will take the Senate, since the GOP is currently unlikely to do well in senate races this year.
If Democrats get a trifecta at any time during those years, they have a serious opportunity to make some significant changes. With Manchin and Sinema gone, they will either eliminate or suspend the filibuster to pass the Freedom to Vote Act (establishing redistricting standards for the entire country) and admit DC as a state (possibly Puerto Rico as well).
Things will start to work against Democrats for the Presidency as we approach the end of the decade, due to generational change, the declining population share of college graduates, and the Electoral College gap, heck they already are in trouble since 2016.
It's a reversal of the previous familiar pattern of R's doing well in Midterms but doing badly in Presidential years, that was the standard in 1992-2018.
