One caveat is that all of us are using the same user radicale user account
This is not necessary, we don’t do that we have the same setup but what I did was I just symlinked the shared calendars, to all the users, see https://github.com/Kozea/Radicale/wiki/Sharing-Collections

Fair assessment – exactly my setup. I should have only used one account like the author. Getting my family set up on individual accounts with “shared” calendars was kind of a nightmare.

I’m still looking for a CALDAV web front-end similar to NextCloud (but not NC). If anyone has suggestions, let me know.