You are stating results, not rules or policy. Where are you getting your source to back that claim? What is your understanding as per the difference between Absentee and Mail-In? Why did Democrats push for Mail-In if they are the same?
No, I'm stating rules and policy. Nevada enacted all mail in voting by legislation, where all registered voters received ballots.
No other state enacted any law.
For starters, your verbiage is not perfectly accurate. You seem to think that "mail-in" voting implies that all registered voters are sent ballots. That's not the case. Mail in voting can mean any procedures for mailing in a vote, which usually requires an application. Absentee and mail in voting can be used interchangeably. See here:
Are absentee votes and mail-in votes different?
Most states require an application be filled out, that was the case in the rest of the battle ground states. For example, Georgia.
Registered Georgians have the option to vote by absentee ballot.
georgia.gov
Or Pennsylvania:
All eligible PA voters can choose to vote by mail ballot. Learn more about voting by mail ballot.
www.votespa.com
Nevada enacted what some people call universal mail in ballots, where everyone is sent a ballot. Lots of nice things about this system. Lots of democrats lobbied for it, no doubt. I don't have a strong opinion. I cherish going to the polling place so I'm not totally in favor, but still there are benefits.