I gave up on using the Roon iPhone app when all I want to do is see what’s playing and switch tracks and adjust volume. It’s too laggy and unstable. For that, the Roon Extension “Web Controller” is vastly superior – it refreshes 10x faster than the Roon app and hasn’t crashed once in over a week since I set it up.
I put some details here. If you have a Raspberry Pi running DietPi or a Mac, PC, or Linux computer (not RoonOS) on your network it’s super easy to set up using a VirtualBox VM. I recommend that method over a direct install on Mac/Win/Linux because the VM keeps everything tidy and isolated instead of spewing node and git files all over your main OS system folders.
Roon really needs to do a rewrite of the iOS app using UIKit so it’s more responsive, stable, and acts and feels like a regular iOS app instead of a weird Android/Linux style app that’s been jammed into my iPhone (including lock screen and hardware volume button integration, which Spotify has already figured out how to do when used as a remote – so it’s definitely possible to do even if the music isn’t playing on-device).