It's also possible the EC gap in 2020 was artificially inflated by many blue states going out of their way to send people mail ballots, etc. during COVID that didn't have those systems before 2020.
It was also artificially inflated in 2020 by the lack of a Democratic ground game in swing states. On the other hand, it was also artificially deflated in 2024 by the lack of a real Republican ground game in swing states. The differences in ground game explain a lot of it, since ground game is focused basically entirely on swing states.
As to your point about mail ballots, it is partly true, but it's also the case that there were very large turnout increases in 2020 in states like Texas where Republicans did NOT make changes to make it easier to vote. Going by current Atlas numbers (maybe not final quite yett), turnout in TX was 11,340,202 in 2024, and 11,326,874 in 2020 (basically the same). Accounting for population increase, that's a turnout decrease compared to 2020 despite there being no significant voting law differences in 2020 and 2024.
2020 was just a particularly high turnout year in general, regardless of whether states made it easier to vote or not.
