Trademark law only stops someone else using the character to represent themselves as Disney, or where is might cause confusion around that. A simple prominent disclaimer can fix that.
That's assuming Disney could ever register the trademark, which is not a given, no matter how often they use it.
Disney can and will allege that the disclaimer fails to prevent confusion and take you to court regardless. And then you have a legal battle to prove that it does “fix that.” A legal battle that will cost you millions of dollars and years of your life, neither of which you will get back even if you win.
The question would be, do you want to fight Disney lawyers to make the argument that your use was not as a trademark, represented as Disney, or that it might cause confusion? With or without a disclaimer.
I'm picking up on a lot of undertones in these comments and elsewhere something like an argument that while it may not technically be copyright infringement in 2024 onward, it will remain de facto off-limits simply from the threat of having to deal with lawsuits from Disney, no matter whether they're actually well-founded. What's missing from that argument is an acknowledgement that there are organizations for the public good that are more than willing to litigate over this (and happen to be bigger targets, too). Wikimedia, for example.
There is no DMCA analogue for trademarks, so, for example, YouTube has no obligation to automate trademark complaints or to resolve disputes between trademark owners and video creators, so almost every case will go through the court, and overloading courts with bogus cases can have consequences for them.
YouTube technically has no obligation to comply with DMCA takedown notices either; there is no direct financial penalty for failing to do so. Rather, the DMCA provides a "safe harbor" exempting YouTube from liability for infringement, then removes that safe harbor if they fail to comply with a takedown notice.
For trademarks, there simply is no safe harbor, and thus no conditions under which it can be removed. That means there isn't a codified process for YouTube to follow; but the stick they can be beaten with at the end of the day -- infringement litigation -- is the same in either case. You can bet they'll do what they can do avoid it.
That's assuming Disney could ever register the trademark, which is not a given, no matter how often they use it.