Mark Levin discusses PA in the above article. You are correct, the Legislature changed the election rules, but it requires a change to the State Constitution which requires a lot to change it. Something like 2/3 yes vote, then put to the voters in a Referendum, etc.
On top of the Legislature changing things (allowing for mail in voting, back in Oct. 2019 pre-Covid), the state courts started changing the Legislature’s rules this year to allow for no signatures, no postmarks, late ballots, etc. Which again was against the state’s constitution, but also against the Federal Constitution iirc.
So, more or less, what I said, but on a broader level to include rules that were put into place, which were counter to state laws (not limited to state constitutional issues). As well as, those administering the elections going rogue and doing whatever they thought they could get away with.
THANK YOU