You are correct, distributions like Kubuntu are not TRULY community-driven as they are still subject to Canonical's influence. Anyone saying otherwise is merely being pedantic.

However it's not Canonical who's running Kubuntu, it's the community, they have the power to revert Canonical's bad decisions, sadly by giving themselves an increasingly higher workload. Most distributions will simply give up at some point, for example VanillaOS' next release will be based on Debian as it was getting too tough to remove snap and all the bad things Canonical adds.

Kubuntu uses snaps which are largely disrespected by the community, that's the end result of being under Canonical's influence. They can't rebase on Debian without effectively killing their raison d'etre and they don't want to remove Snap, perhaps because it would be difficult but most likely because they're deep under Canonical's influence, they look up to Canonical to some extent.

This is, in fact, the very meaning of "influence". It's even worse, in fact, much, much worse for Fedora, they have been culturally enslaved by Red Hat, sorry for the strong word.