It is very unlikely going to happen but lets say before August 2022 of this year Fox was broken off from Disney, and If Fox had the F4/X-Men rights with them, would they have time to pull off something quickly to keep the F4 rights like for example a Dr.Doom movie and they just get a cast and crew quickly to make a movie before the August 2022 deadline?
1st that's an unrealistic scenario. It's not only very unlikely to happen, it's borderline impossible to happen.
Even if the current administration tried to break it up Disney would sue and would undoubtedly win. People underestimate how big streaming is and how far ahead Netflix is. Analysts have argued that Disney needs another large acquisition or two to properly compete, especially since Netflix has started acquiring as well. Such litigation could take months, maybe even years.
2nd. The X-Men, Deadpool, and F4 licenses have already been made null and void. It has been returned to Marvel Entertainment and therefore it's under Marvel studios. The likely scenario is that the two subsidiaries simply agreed to terminate the licenses. That's why it's not under 20th Century anymore.
3rd. Disney has already fully integrated Fox under its umbrella. That includes operation, accounting, management, etc. A break up would take months, if not years, to do and would be required.
4th. Let's say 1-3 are not true and the current administration can break up the company today and it takes effect tomorrow. It's highly unlikely Fox would have enough time to integrate again and start production by the end of the year. They don't have a script or screenplay in hand. They don't have anything in hand.
You have absolutely nothing to worry about. X-Men, F4, and Deadpool are home for good.
