

You can disable Edge if you don’t want people launching it… “accidentally.” There are a myriad of ways. Most recently I’ve used Edge Blocker, which does what it says on the label. Note that this will cause the opening of any file types associated with Edge by default to silently fail if you don’t reassign them to some other program.
The install Firefox and uBlock origin. Unless your parents deliberately go out of their way to download and install Chrome (and depending how heavy-handed you want to get you could even prevent this by busting them down to a limited user account) they won’t have any choice but to use the correct browser installed on their system. That is to say, the only one.
I.e., the one that still supports WMR virtual reality headsets and hasn’t had the functionality for those artificially pulled.