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.

Ok, let me see if I understand this: We have two differet shows, both of them feature male lions as main characters, one called (S)imba and the other called (K)imba, both have a talking bird as sidekicks, both had their father killed when they were cubs, both of them talked to their dead father in a vision on the clouds.
Both shows feature a black haired lion with a scar in its left eye as a villain (with a group of hyenas as henchmen).

How you can call all of those similarities "superficial" is beyond me.

https://www.youtube.com/watch?v=vHps2iC8W3o

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.

I'll repeat: The most you can really make an argument for is that Disney lifted a few visuals.

But honestly, I doubt it was much.  Most of that supercut you have, is just that, a supercut.  Scenes are pasted together across several different episodes to build a Lion King scene.  And to pad things out, there's a ton of generic stuff that you would expect two properties with animated lions and other African animals to both share.

I seriously doubt that talented Disney storyboarders spent their time watching 100+ episodes of cheap Japanese animation to piece together visuals for a movie with a completely different story and tone.  And if they did, surely one of the animators or storyboarders would have spilled the beans in the years since even though most are either not with Disney anymore or completely out of the industry by now.  If it's a conspiracy, it's a remarkably closed-lipped one.

And it would be a pointless conspiracy at that.  Movies take inspiration from other movie's visuals all the time.

Also, for what it's worth, Dune is one of Star Wars's lesser inspirations.  The desert planet and the brief mention of "spice" (since excised by the Solo movie) are kinda all that got on screen.  Some of the earlier scripts have a bit more though, particularly Leia's cut Bene Gesserit-lite backstory.  It's not nothing, but it's small in comparison to how much Lucas openly lifted from Kurosawa, Buck Rogers, Lensman, and The Dam Busters.

I call it superficial because it is.  Maybe they did lift talking to the father in the clouds and/or Scar's look.  Maybe they didn't.  It's not like Bubu is the first time a villain has worn black and had an eye scar.  And talking bird sidekicks and dead parents aren't exactly new to Disney.  They're both in the true prototype, which is Bambi.

But if you actually watch the two, The Lion King and Kimba are just completely different to the point of it being almost laughable that it's a controversy.

1: Again, though, I've gotta ask: Why lie? And how have they managed to keep the lie all these years without someone saying "Yeah, we sat down and copied all that"?

2: People in Japan would have been thrilled to see a nod in Tezuka's direction and it would have probably helped sell more tickets. It's not like there's enough similarities for there to be any legal action.

Going to break my own rule and post a video.  It does more to debunk this ridiculous urban myth than I could by words.  As I've said, all you have to do is actually watch Kimba to realize that they are not the same at all.  Well, we finally have a YouTuber that's done exactly that and, surprise, surprise, a few selectively edited videos don't hold up to scrutiny in the slightest.