If push comes to shove, you can always create a note over the same place and mention “sorry I effed up here but don’t know how to revert :(”

Yes, but similar to Wikipedia (where the same holds true) the forces fo good and honest seem to prevail.

Quad9 is decent, but there’s some weird legislative issues (they can be court ordered to not resolve certain sites) BC weird reasons.

If you have a raspberry pi or similar sitting somewhere, you can set up a pihole DNS with unbound as upstream. Then you’ve got a DNS that’s as private as you want, locally cached and with additional ad/malware/… blocking capabilities.