the time is accurate. twitter displays the time of the tweet for the timezone your IP is in. but it doesnt necessarily mean POTUS was up tweeting at 230 in the morning. you can pre-compose a tweet and set it to post at a specific time if you want.
with nearly all the votes in (~143mn), and there being 235mn eligible voters, that a turn out of ~%61. which is a pretty consistent turnout since 1992. i guess all the attention this election has gotten, hasnt actually inspired moar americans to get out and vote than usual. just enough to give biden the win, a week after election day.
seems legit.
https://www.usatoday.com/story/news/politics/elections/2020/10/22/voter-turnout-2020-ranking-us-presidential-elections/6006793002/
its literally provided in the sauce in OP. heres some moar. 235 million eligible voters. do you even internet anon?
http://statchatva.org/2019/11/11/elections-2020-projecting-eligible-voters-by-state/