The current system with multiroom is extremely cumbersome and thus feels unpolished esspecially for a paid feature. Switching between servers UI to modify each one isn’t ideal and is messy when trying to share your system with others in the same house or guests who may not be tech savvy at all.
The solution I see is having a master UI system in multiroom that can be on the the server of your choosing and have that UI alone operate the different zones. Having the other volumio servers be slaves that will only pipe to the master server through the wifi and thus not show up as multiple servers in the Volumio app and on Spotify in such a confusing way
In order to have ultimate control, you could have guest accounts available, those guest accounts can have a series of permissions attached by the master.
One permission can turn on and off which zones that an account will see, one permission will be to turn on and off what accounts will have visual access to the song that is that is being played on each zone, another to control what zones an account can control music on, and one setting for each zone that will determine which accounts can override music played by other accounts.
I would like to leave the ability for each zone to have, no accounts which can override besides the master, so whats playing on a speaker has to stop first before anyone else can control it. But also allowing some accounts to have more permissons on some zones, like that persons bedroom, but not another, like somoene elses bedroom.
This way you can have full control on a user to user, zone to zone basis as to what each user can control music on, this will eliminate fear of crossing wires when it comes to whats playing where and what servers are connected to what, because they will all always be connected to the master UI, its the permissions that will control who has the ability to override what.
You could have spotify connect to the App and then have them sign in on the volumio app with the main or guest account and control the zone settings from there.
Later you could create better unification by either getting spotify to add more features like zone control or to add spotify controls to volumio itself for more in house volumio app control. I could suggest mimicking or working with Spotube if you desire in house app control or open source controls in general for spotify. GitHub - KRTirtho/spotube: A lightweight free Spotify 🎧 crossplatform-client 🖥📱 which handles playback manually, streams music using Youtube & no Spotify premium account is needed 😱
All that being said however I feel a two app system is much easier to deal with than a multi UI system, having to switch between many UI’s and risking crossing connections, rendering it being barely usable for anyone who isn’t savvy with the system (Aka anyone who isn’t the person who set it up), and difficult to use even for those who are savvy with it.