Firefox on Android phone refuses to sync

For years, I've been using FF on desktop (Linux), tablet (Android) and phone (Android - Samsung S24+). Sync has never been a problem until two weeks ago when FF on the phone has either refused to sync when I tapped the command, or hasn't synced for many hours or sometimes days (which is why I tried to do it manually). So, I signed out of my FF account on all 3 devices and then signed back in. The desktop computer and tablet are syncing normally, but the phone still won't sync. When I tap the 3-dot menu on the phone and then my name, it says the phone has NEVER been synced and tapping the sync command does nothing. Under "Choose what to sync", all options are checked, but greyed out. Can't change them, in other words. When I access bookmarks on the phone, it properly shows what was there before the last sync. The phone is running FF version 150.0 Build 2016155439

Help!