...Trump is convicted in Georgia?

Firstly, he cannot pardon himself from a state crime. So that's off the table.

It may be unrealistically quick, but suppose he is in a GA prison. What then? I don't think the feds can demand his release if he won the election as that would be overstepping federal authority, would it not? I would think GA would not be under any obligation to release him. Immunity wouldn't apply because the crime -and in this scenario, the punishment- predated his becoming POTUS. But realistically, you can't run an administration from a prison.

There is no precedent, obviously. But I don't think GA could be compelled to release him.

Even stickier, what if he is convicted after becoming POTUS? No pardon, so he has to present himself for incarceration. But how does GA make that happen if Trump doesn't agree? Plus, while the crimes predate, the conviction post-dates, and I don't think there are mechanisms to imprison a sitting POTUS.

The closest I can come up with is the 25th. If the POTUS is unable to carry out his duties (which I think prison would qualify), he is replaced.

Someone needs to draw-up an Amendment that a person serving a prison sentence cannot hold office until he/she is released. Too late this go-round, but clearly our Founders never anticipated this. Hopefully, it will never happen again, but an Amendment would be nice to clarify.