There are lots of folks here way beyond me in experience. You’re doin’ excellent. 
We all start somewhere and all have different experience levels for these things so no worries. It’s easy to cross communicate in these areas so nobody worthwhile is judging anybody for it.
Some days I just want my Sony MD player back!!! I’ve got a Touch, Nano and a clip Shuffle around here somewhere too. I use the Touch for handing music control off to others in the car or at home without having to hand my actual phone over.
The “download” option is a lot more limited than the full app but I use it for times I can’t connect back to the server (like on an airplane). Smart playlists will auto-update so I have a few of those I have setup as downloads so I always have something to play for a few hours.
For Settings→Playback→Caching here are my settings:
Wifi\Cellular cache ahead: 40 tracks
Cache size: 1GB (Plex will hold onto tracks it’s already played, this is probably overkill for me)
For Settings→Downloads here are my settings:
Quality - Max
Everything else enabled so smart playlists auto-update and such and “prefer downloads” at Always.
You manage how much space it takes up just per playlist… I think. That’s how I do it anyways. Someone else can chime in with more specifics maybe if that’s a question (or search for another topic on PlexAmp download functions maybe).
This last time the Plex server locked up I didn’t notice until I was done with chores because my caching kept playing the queued tracks. I won’t notice the “crash” unless I do something in the PlexAmp that requires checking back in to the server. Having 40 tracks ahead cached is about 2-3hrs of music.
Sure!
I have 3 wireless access points in my home - meaning 3 different wifi connection points that devices can use. This helps make sure I have good wifi coverage around my house (which has old construction with wifi killing materials in the walls), backyard and a detached garage. As I move around the house or go to the garage and around the outside of the house my device will switch to the AP that provides the best connection. This hoping could replicate a similar situation as “going remote” if the bug is related to communication\network route changes. I could see a bad communication loop in the server eventually locking it up (odd but possible).
Well…. I’m on the beta now and had the bug today so that wasn’t the fix. It was still a good idea to try it out and see if it helped and having more information, even if it’s a failure, can help with troubleshooting.
So if you were inclined to try it to get a fix… it doesn’t seem to be a fix so there’s probably less inclination for you to upgrade to the beta.
If you want to though…
Totally fair to be safe! Backups are king!
Here’s the generic “backup your server” article: https://support.plex.tv/articles/201539237-backing-up-plex-media-server-data/
So for Syno the easiest way is to just copy the entire Plex Media Server directory if you have the space but you can skip the caches folder to save some space. This FAQ from ChuckPa gives you file locations (and lots of other good Syno info in that FAQ topic - not sure why it isn’t pinned under the Synology specific forum but it’s in the “tips, tricks” forum area): Synology FAQ - Questions, Answers, and How-To's - #18 by ChuckPa
I think you should have a “Plex” share though and that’s where it’ll be (I used to run Plex on Syno but it’s been a bit now and can’t remember - QNAP you gotta do a trick).
It might be good to setup a regularly scheduled backup for it. You should be able to setup a Hyberbackup task on your Synology if you wanna automate it (I backup mine every week so I don’t lose too much watch history).
You don’t have to backup your media for this process just that directory.
If you have to do a restore you essentially just copy back that directory. I have never had to do that even with several upgrade\downgrades under my belt on Synology and QNAP but it’s always good to be safe.
So far the current beta has been pretty stable and out for a few weeks now without any obvious gotchas.
If you wanna do a bit more you can use ChuckPa’s DBRepair tool to help with Plex Media Server maintenance as well. Includes backup\restore option but it’s more of an SSH\Terminal app and some folks aren’t comfortable with that but this is pretty well detailed tool.
GitHub: GitHub - ChuckPa/DBRepair: Database repair utility for Plex Media Server databases
Plex topic: DBRepair development - if you have trouble with it try there.
At this point, it’s clearly a recurring problem so should be replicable but pinning the right scenario down might be hard to do for such a small user base impact. Hopefully a dev will get some inspiration and can draw out the missing info based on their more intimate knowledge of what’s happening in the apps.
So as Plex Media Server and PlexAmp update we’ll just keep trying things and uploading logs and hopefully it’ll get narrowed down.
