"How did Sora beat MX with x-balde"
Sorry but this typo kind of cracked me up. Just imagining them explaining the reason why Xehanort lost his hair and had super veiny skin was because Sora splashed him with some new type of hair removal solution called x-bald.
...but on a more serious note:
In KH3, Sora's strength alone wasn't enough its just that Donald and Goory are actually really f***ing strong. Cuz unlike Sora, they got all the combat experience from KH2 and maybe some off screen training. Sora didnt win cuz of some undefined power friendship, he won by the very well defined powers of himself, Donald's and Goofy's who he is close friends and comrades with.
In all the games the "power of friendship" has always sort of been code for what has given the characters the strength to not give up. Basically, what keeps them going when they are getting wrecked--to keep standing up and saying nope, I got one more round in me because I want to keep my friends safe so I refuse to go down.
KH2 final boss fight in particular was a back-and-forth with Sora and Riku both supporting each other to get the job done. If either of them had been missing Xemnas would've won hands down.
I think of all the games, Re:mind had the absolute strongest "friends are my power" moment. I
really felt that line when Sora used it when everyone was finally there all together able to blast the living bejeebus out of MX. It had impact, I think, because finally out of all the garbage they all had to wade through to get to that moment they were ALL there, still standing, supporting each other.
So you aren't wrong in saying yes, they definitely do need raw power and strength to overcome their opponents---but it has also been a recurring theme that in the kh final worlds/final boss fights one or more characters has moments of "I'm not sure I can do this..." or feeling helpless, overpowered and/or terrified. Sheer strength isn't going to save those characters from those moments.
