Basically I would do exactly the opposite of what MLB did for 2020. No DH (in either league), 9-inning games in doubleheaders, and no runners on 2nd to begin extra innings. The DH and extra inning runners take away strategy and excitement, and the 7-inning doubleheader has never made any sense to me. In 2020 they said it was implemented to take away contact between players, but how often did players from different teams come into contact with each other for long enough to be deemed a "close contact", and that isn't applicable in 2021. Not to mention the no-hitters that could have happened that were in 7-inning games that weren't counted. There have been 8 no-hitters in 2021. There are 2 more if you count the ones thrown in 7-inning doubleheader games.
"Perfection is not attainable, but if we chase perfection we can catch excellence."
-Vince Lombardi