Florida requires all absentee ballots to arrive by Election Day. What this means in practice is that if a mail ballot arrives after Election Day, it will not be counted. This might seem drastic, but remember, mail voting is the exception, not the norm.
North Dakota, along with 17 other states and the District of Columbia, accepts ballots that arrive after Election Day. Some even accept ballots that arrive up to two weeks after Election Day.
Accepting ballots that arrive after Election Day is the primary reason for the delay in election results. When a state allows ballots to roll in for weeks, results will be delayed for weeks.
But it gets worse. Not only does accepting mail ballots that arrive after Election Day lead to delays in election results, but it also violates federal law. The law requires a single national Election Day to be held on “the first Tuesday after the first Monday in November of every even-numbered year.”
https://thefederalist.com/2023/07/10/why-has-election-day-turned-into-election-month/