I had a similar issue trying to create an Apple TV account. I already had an Apple account that I was using on my work laptop (first mistake - I should have created a work account there instead), and for 2FA, I needed to wait for a code to pop up on that laptop. It never came. There was an email alternative, but that also didn't work properly (maybe only on certain devices, IIRC?). Apparently in the settings you can request a 2FA code, though, so I did that... but that only had five digits, whereas I needed to give six for the code to work. Eventually I figured out that Apple had just forgotten to zero-pad the 2FA code out to six digits, so I needed to add a leading zero to make things work.
The worst part of this is that now my Apple TV account is linked to a laptop that I don't always have on me. And even if I did have it on me, I don't want to get a laptop out and turn it on just to do 2FA. I already have a TOTP app on my phone, just let me put everything in there and leave me be.
My experience with MacOS is generally that it's about as buggy as my home Linux setup. That's partly a testament to how solid Linux can be these days, but at the same time, it feels pretty damning considering only one of these operating systems is free (in any sense of the word). And that's not including stuff like the configurability of the whole thing.