Invincible is miles worse in that regard so its baffling to me that that is the one they chose to adapt and managed to get super popular.

Probably because it's written by Robert Kirkman who also wrote the comic for The Walking Dead, so execs were looking to jump on another of his projects and at least Invincible was finished. If they try to do the same again with Fire Power then at least comic readers will know it won't end up being done well in part because of how badly Invincible has been mismanaged but also because despite a good start Fire Power doesn't end anywhere near as well as it could have.