You're correct. This is basically a conspiracy theory more about slamming Disney than investigation. There are a few superficial similarities and sometime in like the 90s the internet ran with it to the point where it's been treated as an unquestioned fact in many corners. Thing was, in the 90s and early 00s the internet didn't really have video blasting from every corner, so the conspiracy could be shown via a few pictures. If the video were widely available the theory falls apart.
Most you can really make an argument for is that Disney lifted a few visuals, but movies do that all the time.
Seems pretty similar to me, there's zero chance at least a significant portion of Disney's animators did not know what they were doing. Tezuka was not exactly unknown, after all.
Inspiration is like Dune -> Star Wars. This is very much lifting and remaking. Of course, there are people who seemingly think, for instance, Sword of Shannara and the first book of Wheel of Time were "original" as well, so yeah.