Hi Joe, welcome to Volumio 
, even though you seem to be having a hard time of it.
Yes, the documentation is indeed in need of a good overhaul, and may well get it after this current transition to Volumio3. Can I also point out that the Community is also cordially invited to improving documentation too, so if you want to help:
https://volumio.github.io/docs/Good_to_Knows/Contribute_to_this_Doc
Your playlists problem will need to more carefully defined, and described so that it can be reproduced … preferably in it’s own post with as much info as possible, including device, Volumio version, and a system log (if you think it might be useful (https://volumio.github.io/docs/User_Manual/Sending_logs_for_troubleshooting.html) . Yes, your playlists are remembered as a feature … even across multiple devices.
There is a ‘Plugins’ category/section in the forum:
and here you will find the Volumio Plugins Collection list.
I’m sorry that you feel like this, and I’d like to think that with a bit of help we might be able to change your impressions to be a bit more favourable.
P.S. I’ve moved your post to one in it’s own right, as I think that you are raising some valid points.