The provision of the 25th Amendment that I believe you’re talking about requires the vice president and the majority of the cabinet to agree, but those people are literally all chosen by the president. Based on Trump’s past behavior and recent comments, it’s likely that he’d only choose people for these positions who swore a personal oath of loyalty to him. So, they’d be unlikely to exercise that power.

Every single opinion about what would happen, including Glenn’s, and mine, and yours, is “just guessing”. This would be unprecedented.

As a prosecutor who appears to be excellent at her job in an adversarial system, Fani Willis is going to always present the situation in the light that she expects to get the best results.

In the end, my opinion, and that of at least some legal experts, which like you said is just a guess, is that practicality would require an agreement between the Georgia state government and the federal government to allow the office of the president to function properly.