In 2020, we did see big gaps emerge in vote method by partisanship and ideology, with liberals/Democrats more likely to vote by mail. That gap didn’t exist before.
Related, it’s always worth keeping in mind that while the counting of votes creates the illusion that a candidate comes from behind, all votes are equally valid. In some places, rather than release vote counts as they are done, election administrators wait and then release results all at one time. With some electoral systems, there’s no other way to do it.