I don’t like Canonical either, hence my recommendations for Mint or Pop being listed first. But let’s be real, if someone wants to just get away from windows and wants something that works without having to learn much new, this is good enough.
Unironically, switch to Linux. Mainstream distros like Mint, PopOS or Ubuntu are very friendly for casual users, have GUIs for everything and if something does go wrong, the error messages actually have proper meaning and you’ll find tons of resources online as well as people willing to help.
Most stuff nowadays runs in a browser anyway, so here there’s no compatibility issues, office is available in Linux through libre office and gaming has come far with steam and proton.
In Europe GDPR gives you the right to have all your data deleted. All you do is send in a request and SO has to remove everything of yours, not just anonymize it. There are some exceptions for legal reasons, eg where financial transactions are involved, but comments should not be exempt.