what did CCA do to ruin him? i was never really a MS Gundam fan because young Amuro was a annoying little shit so it stopped watching.
CCA is extremely frustrating because it pretty much ignores any character development post-0079. The film basically acts like Zeta never happened, and that hurts all the characters involved, particularly Char.
Basically, Zeta has Amuro and Char teaming up to take on an Earth government that's gone out of control. It takes Char away from being a character who's purely revenge driven and humanizes him. You can tell he genuinely cares about humanity.
CCA turns him into an egomaniacal dictator of a new Zeon force (With zero explanation of how he even rose to power). He also wants to drop an asteroid on earth so he can drive humanity off it and let it recover from the damage we caused, which isn't something that makes any remote sense given the Char we see in Zeta. All this feels purely to set him up in a villain role so we can see a conclusion to his and Amuro's rivalry. It's awful.
Amuro also gets shit on a bit as well. The relationships he develops in Zeta are promptly dropped with zero mention and he's back in good graces working with the Earth government. Even though he took out the force in the Earth government that was abusing power, I don't think it makes much sense that he would go back to a high ranking military position after seeing all that.
Since you didn't finish 0079, I highly recommend checking out The Origin manga. It's really the perfection of that story. The art is amazing and the pacing has really been fixed. Amir does start as a whiny shit, but he develops over the course of the series into someone likable, or at least relatable. Also, The Origin treats him and Char as co-protaganists, so you aren't stuck seeing things just from his view for the whole time.