Good concept, but in my opinion, the story should be rebooted from the start.
So you've got a Vongola/Gundam in Marvel with system concept, a combination which is pretty unique.
What makes Katekyo Hitman Reborn great? Tsuna's relationship with his guardians, and how they learn from the first generation mafia family.
What makes Gundam great? Giant robots, character relationships and the world conflict.
What makes systems great? A clear progression for the MC, and fun lotto.
What makes the MCU great as a location to set your story in? Everybody's seen the movies, so it's instantly recognisable.
The main problem I see is that Giotto is the only real character, and he's got all the powers. But you made him too OP, so now you have to nerf him in the latest chapter.
Again, this is only my opinion, and it doesn't really matter if you don't take it into account, but your first priority should be to delegate.
In a KHR fanfic, the first thing to do is assemble the Vongola famiglia. through the system Gacha, by recruiting Marvel characters and giving them rings... it can be anything!
then you can specialize: for example, Tsuna has two mechanics, you could give the job of building gundams to a guardian.
I think your story has amazing potential, so whether you keep going on or start over, I wish you good luck.
All you need to do is think things though, and not skip though important things too fast (like finding the kingpin just like that without explanation)
