I'm not sure I fully understand your statement here.

(For purpuoses of this conversation, I'll be limiting my comments to U.S. law. I can't say I'm any expert on that, even, but as little as I know about U.S. law, I know far less about any other country's law. IANAL. Not legal advice.)

I'm referring to this intro sequence that they've started adding at the beginning of the significant majority of Disney movies and TV shows. (I don't think they add it to Marvel or Star Wars things, for instance. Only to more explicitly Disney-branded ones.) It's probably restored, but it's the clip from the original Steamboat Willie short.

When you say "you can't claim only part of an intellectual work" I assume you're referring to copyright. But what I'm saying is that Disney has finally accepted that they can't prevent copyright protections on the original Steamboat Willie short from expiring on January 1st 2024 (I don't think there's any likelihood of them pulling out a last-minute surprise before then) and are changing their approach. They're trying to establish a case that they're using Steamboat Willie (or that clip, at least) as a trademark. (Trademark law and copyright law are different. The rules are different.) I don't think there's any reason to suspect that a part/clip of the original Steamboat Willie short couldn't be used as a trademark.

If someone made/released a film featuring Steamboat-Willie art of the Steamboat-Willie Mickey Mouse on January 2nd 2024, that would be fine from a copyright perspective. (So long as they didn't do something else that infringed on copyright somewhere.) But it looks like Disney has specifically taken steps to ensure they have an option to come after such a person on trademark grounds.

Now (oh blast, I said I wasn't going to talk about non-U.S. law, didn't I? I guess I lied), my understanding about Blood and Honey is that a) it was made in Great Britain and b) the copyright in Great Britain technically hadn't expired when Blood and Honey was released. Basically, Blood and Honey was (technically) a pirate film. It wasn't (technically) allowed. (Any more so than would be an unlicensed romcom starring Darth Vader and Jar Jar Binks would be in the U.S. -- both characters from works that are fully covered by copyright.) In fact the director of Blood and Honey has said he's shocked he hasn't been sued yet and that if Disney did sue, they'd probably have a case.

Now, theoretically, if someone had made a movie in the U.S. with Winnie the Pooh as a character after January 1st 2022, that wouldn't have infringed any copyright so long as they used only art styles and story elements and such from what Winnie The Pooh works had entered the public domain. Mostly just the original Milne book.

There was a court case where someone made an unlicensed Sherlock Holmes book while some of the original Sherlock books were still in copyright but others had passed out of copyright protections and the courts basically said that you can use any element of Sherlock from the public domain books, but not any elements (such as his dog or his bipolar (which I'm guessing they called "manic depression") diagnosis) that were from works still covered by copyright. (And it sounds like you understand that last bit. Just wanted to add clarification for other folks that might see this thread.)