Windows 11 IoT LTSC is the best answer at the moment. I've had no ads, no AI nonsense, the only setting I've had to change is to restore the sane position of the start menu. Oh also I did use the default options in Rufus which I think disables some annoyances. Despite all the moaning about it, Windows 11 itself is actually a small improvement on Windows 10 so I'm happy to upgrade.
Overall it's is a lot nicer than dealing with Linux's downsides (I have enough of that at work).
I'll stick with this until Microsoft forces my hand.