Trump has 80% to 90% approval in the GOP, depending on the poll.
(Link to poll showing 87%:
https://thehill.com/hilltv/rising/476978-trump-support-among-republicans-reaches-all-time-high-in-poll)
Assuming he holds at least 80% of the GOP vote, what percentage of the Democrat vote does he need to win?
Latinos:
As much as 45% of support Trump (
https://www.nbcnews.com/think/opinion/trump-has-latino-voter-support-s-strong-ever-why-haven-ncna1240168)
LGBTQIA+:
As much as 45% of gay men support Trump
(
https://www.nbcnews.com/feature/nbc-out/trump-applauds-poll-showing-45-percent-support-among-gay-men-n1240633)
Blacks:
As much as 24% of African-Americans support Trump. While low, GOP usually has single-digit support among black voters.
(
https://www.washingtontimes.com/news/2020/aug/31/trumps-approval-rating-black-voters-soars-60-durin/)
Unions:
As much as 47% of Unions supporting Trump. Probably because: JOBS!
(
https://www.politico.com/news/2020/09/22/donald-trump-union-support-snub-joe-biden-418329)
Seems like Trump is keeping the bulk of his base, and possibly really diving into traditional Democrat voters.