This is good news, and I'm hoping Marvel gets it right, because they should have BEEN done the Fantastic Four by now. Quantumania should have been a Fantastic Four movie IMO.
Reed Richards was always a linchpin character who was crucial to the Marvel Universe as a whole. He was always the go-to guy whenever the world is being attacked or threatened, just like Tony Stark in the movies. Bringing him in earlier would have kept some of their narrative cohesion once the Avengers disbanded.
A lot of cats write the F4 because the movies were weak, which is a shame because they're arguably the most important team in Marvel. Stan Lee and Jack Kirby knew what they were doing.
They were the first superteam to be written like regular people and not just flawless paragons, and they have a top 5 rogues gallery in comics. On top of that, the Marvel Universe was built on the success of the Fantastic Four. Their success paved the road for the emergence of the Avengers, X-men, Black Panther, Galactus, Doom, etc.
Half the Avengers/X-men/etc's costumes are made of "unstable molecules" that Reed Richards developed, right down to the fabric of their draws. Reed Richards is HIM in-universe, and having him around will give Marvel some much needed direction and help to establish a protagonist group worth following.
None of us cared about the Avengers until the movies started dropping, and we all see how they crushed the buildings. That's because the Avengers are a linchpin team in-universe. The F4 are linchpin characters, and they're not as lame as people think.