First Steps IS a pretty infantile title. However I'm guessing it's either a reference to them being astronauts (the first people to go beyond what we were allowed to do, thus bringing Galactus here) OR it's supposed to be infantile because the society they live in is essentially sheltered and oblivious to any sort of real problems, now their innocence is being shattered. That second one is probably giving the moviemakers way too much credit though.
Galactus being wasted on an origin-type movie is really bizarre, because as someone else said there's nothing to escalate to after that. Unless this is a setup movie and Galactus is going to straight-up obliterate the world of the F4, causing them to end up in our world/time to join up with the MCU against the threat that's following them, or something like that. In which case, if it's a setup movie, why are they doing it before the Dr. Doom movies? Galactus is pretty much the only thing they have left to escalate to after Dr. Doom.
My guess: Galactus wins in this movie, Dr. Doom wins in his first movie, the multiverse gets smashed together, the new Avengers (w/ F4) defeat Doom in the second movie, then the MCU moves to the final phase of dealing with the coming of Galactus. Or they'll just kill Galactus in this movie and then show up to help with Dr. Doom IDK
And yeah, the F4 were never actually that interesting, and the box office for their movies demonstrates that. They were big in the Boomer Times and that's about it. Lot of people will be eager to jump on the bandwagon and pretend they're F4 fans, though, much like what happened with some of the other MCU properties. Tons of Johnny-come-latelies in the Marvel fanbase.