You can use equivs to create a dummy coreutils-from-uutils package, as mentioned in the responses to that report.
It is frustrating that Canonical has no interest in fixing it, though. It makes it hard to take their claims seriously that you can still use GNU coreutils if you want.
You're specifically frustrated about unbounded stack recursion exhausting the stack, triggered by multiple thousands of directories? It doesn't sound like this is about multi-thousand-deep directory structures, it sounds like it's about something else.
Because even diving into it, I would agree with a prioritisation decision that puts this bug down the bottom of a priority list.
Canonical is just rushing the switch because they want to get rid of software with GPLv3 license, not because there is any technical merit for doing so.
If they want the default to be non-GPLv3 Rust-based that's fine, but some of us don't care (and want the same behaviour everywhere, like on RH-based systems we may also have) and they should leave the GNU as an option. Potentially both could be installed at the same time (it's what update-alternatives is for after all).
That's a better thing to discuss, and I'd expect there to be better bugs to talk about to go with it. Stack exhaustion in an unrealistic environment should be fixed, but a "stop everything" bug it ain't.
It is frustrating that Canonical has no interest in fixing it, though. It makes it hard to take their claims seriously that you can still use GNU coreutils if you want.