Google Docs if you have editing privileges you can switch to suggesting mode and it will allow you to “suggest” changes (diff like) instead of outright make them, I usually like doing this for documents which aren’t mine.

Notion I agree but it does have a way to lock a page so you can explicitly unlock it to make edits, more clunky than having a “suggesting mode” but it works.

And both product actually have history so if you do accidentally blow away something or add garbage you can revert to the version before you made accidental changes.