It’s worth pointing out that the reliability/stability of the LIbrem 5 seems to vary from one example to another.
I have two Evergreens, which i assume ought to behave identically if the software is identical. But they don’t.
The first (lower serial number) has the ‘blank screen on startup’ problem discussed elsewhere on this forum, and then problems seeing the modem or WiFi adaptor after being lucky enough to actually get prompted for the LUKS key. Six attempts (and typically 10-15 wasted minutes) to simply get the device into a usable state in the morning is not unusual.
Also, regarding Bluetooth audio. I only ever tried connecting it to my car’s receiver, but it never succeeding in pairing.
However, the second L5 (which I bought second-hand more recently) has none of the above problems, even after I cloned my disk image from the first L5 to it using Jumpdrive. I’m not saying it doesn’t have any problems that sometimes force me to reboot it (such as it occasionally being impossible to re-enable cellular from the soft-key), but its overall reliability is in a different league.
The problems you are having – and particularly with the unexpected shutdowns – suggest that you may have been even more unlucky than I was with my first Librem 5.