...shared with "Everyone", no password needed).
I don't understand why so many people still think this is a good idea. This comes up several times each week on this forum.
With the increase in malware attacks in recent years, no security is asking for trouble at some point in the future (look up Wannacry to understand how that was spread). Probably you can fix your settings in LibreELEC to work, but you'd be better spending the time to set up proper username / password security on your PCs. You'll need to do it sooner or later.