What SiL said.
Well, that is actually part of the problem I say.
The bigger/better thing has only ever happened in the comics, the Aliens only actual win has been Hadley's Hope on screen, and even that was short lived.
If you never actually make the Aliens threatening on a grand scale then they become just giant space bugs because.............that is all they have been shown to be.
You need the Aliens to take over the earth or AT LEAST a large colony world just to remind/show people they are capable of doing so. The Alien itself has essentially become Jason/Freddy in space. They show up, kill some randos, and get stopped again until they are reactivated for the sequel. There is no actual progression with them as a menace.
This. I think they should start with a detailed and long survivor story about a very large colony/space station/city that got infested. I believe the aliens can be shown as a mass that overwhelms but just as often show few aliens being horrifically creepy, lethal and cunning. It's not impossible to marry the two approaches, they are perfectly compatible IMO just depending on context.
I enjoy Book 1's Earth invasion segments above all else in the book. Especially how it was expanded upon with just a few pages in the novel. I do want to see more of that. Invasion on a mass scale. That to me shows the threat and full potential of these creatures. That's also scary if done right, not just a haunted house in space.
(I will not comment how ridiculous it was that in Book 3 all of the aliens gathered at the same place and got nuked, the comic version was better with at least the method of alien annihilation, but no method guaranties every alien will be wiped out once they take over Earth.)
And yeah, I also really liked both Titan trilogies. Full of problems, but I especially enjoyed the Rage War. Again, the Rage were a mix of meh and ridiculous, and the aliens weren't treated as a real threat always, especially hated that they needed to be augmented with breathing gear and suicide exploding nano things, like they don't explode from gunfire already, but the world building was so nice to see!
IMO, Titan has been killing it with these novels so far.