Part of the problem with doing a Fantastic Four movie is the general audience knows fuck all about the series other than Doom and Galactus. In the four most recent movies of this family there will now be two+ that were about Doom and two that were about Galactus because nobody gives a shit about Mole Man, Puppet Master, Annihilus the Negative Zone and the Annihilation Wave, or any other FF villain.

The best thing a reboot should do is start small with a street level villain like Puppet Master because that not only let's the story introduce Alicia, but also permits mind control for the family to fight each other as the big draw of hero stories is always when they fight each other, not whatever villain is showing up this issue/week/event. That's why the first Avengers movie was as successful as it was, the team fight each other more than the villains, and mind control only happens for a few of those fights.

End the first film teasing the next while also escalating the threat, but for the sake of Stan Lee's mustache stop doing origin movies that also immediately jump to literal cosmic level threats. It just means everything that comes after is lackluster and the MCU shows this with everything that happens after Endgame and Thanos.