Absolutely. You can install the older\public version just like you would when upgrading\updating. There’s a couple ways to get to those installers as well - here’s a quick Q\A topic on getting older versions (if you don’t just want the current public version): How Do I Roll Back to the Previous Server Version?
For 1. - I too tend to experience this when remote rather than local.
For 2. - I’m using QNAP and iOS PlexAmp but there’s a couple different environments reported here - but seems like iOS clients - so it feels like it’s not a server environment specific issue but maybe iOS thing? I also switched from iOS18 to iOS26 now which also impacts testing and troubleshooting.
For 4. and 5. - Because Plex is very server\client designed it’s likely a combo issue. Plex clients often flake out hard when contact with the server goes sideways as there’s no real clean function between “live” and “offline” for Plex clients or PlexAmp. PlexAmp will continue to play cached songs but any new fetch activity will throw it off and you’d have to switch to the specific Downloads section of the amp to continue - which sometimes doesn’t work unless you close\reopen Plex\PlexAmp on the client. The fact the Plex server is what crashes is very odd.
For 6. - the beta is server beta, I don’t think there’s a beta program for PlexAmp but I could be wrong (I will now wait for the collective gasp).
For 7. - without knowing what is causing the crash this can’t be answered yet. Since it’s not happening to a lot of people (there’s lots of folks using PlexAmp and only a couple of us in this topic) and not reproducible by Plex dev, it’ll be tricky to track down without more comparative troubleshooting and logs. Even logs might not show stuff because the crash could take it down before a log reference can be, well, logged.
None of my music transcodes so I don’t think it’s that, but it could be something with a character set not playing well (that’s happened before) or bit sequence in the encoding throwing it off (at one point back in the day a particular version of LAME encoding messed up playback on Winamp). The fact it crashes the server entirely - while QNAP\Syno report it’s still running - is very odd.
I think trying the server beta is a good idea as Plex has focused on the new transcoder release as the next public release and one of those fixes might address this bug even unintentionally (since we don’t know what’s causing it) - like the “missing data” fix Atomatth mentioned.
Personally I haven’t run into the problem again after switching to the latest Plex Server beta 1.43 but I haven’t done a good solid test as it’s dang cold and I haven’t been wandering away from home with music playing lately. 
