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.
legofreak
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.
You can always compile from scratch, compare the checksums or use the version you compiled. In projects this large people usually do this, and there's a certain level of trust that these checks have been performed.
Mint looks quite similar, and if she asks "Microsoft applied an update and now the start menu looks different."
If all she does is browse the internet and read emails, she'll never know the difference. You could even set up the splash screen to display the Windows logo or just disable it all together.
Wikipedia itself is pretty great, the company and its marketing behind it, not so much.
https://www.dailydot.com/debug/wikipedia-endownemnt-fundraising/
The transition from EVs to public transit, biking, etc has to come eventually, too. We can however already do that and places have successfully done so. Look at the Netherlands for example. EVs are in the way of transitioning to better public infrastructure and will only delay it.
Proton serves privacy, not anonymity. They will not collect, harvest, analyse or sell your data. If you however use their services for illegal things they will forward whatever - usually little - unencrypted information they have about you.