[Edit: I made some mistakes and some states have changed. New post
here.]
Not all states accept absentee ballots that arive late. The ones that do are as follows, according to this website. (This might not be entirely accurate. The page says some states may have changed policies due to Corona, but I'm not going to look that up for all 51 of them).
1 day:
Texas
48 hours after polls close:
New Jersey
Noon of third day after election day:
Virginia
3 days after election day:
California
Kansas
North Carolina
5 days after election day:
Washington
6 days after election day:
Iowa
Utah
6 days after election day for postmarked ballots, one day for those with no postmark.
West Virginia
7 days after election day:
D.C.
Minnesota
New York
10 days after election day, by 10:00 AM:
Maryland
10 days after election day:
Alaska
Ohio
14 days after election day:
Illinois
Apparently no limit:
Nevada
So if all this is accurate then I presume the worst-case semi-plausible scenario involves one party narrowly winning Ohio and narrowly winning the electoral college - and then the absentee ballots flip Ohio with its 18 electoral votes.
Have I got this right?