Potentially any screen that you can plug a Chromecast into would work. I have some portable screens that I use for my factory that are 15" (so probably a bit big) but I think that you can buy smaller ones and just use it as a now playing display
I have a couple of Google displays (including a Max in the living room) and it should be perfect, but sadly Roon doesn’t work well for more than 10 minutes without making changes that annoy the rest of the family and talks back everything you do
The Rose had really the best display, but if you want to use it not as Roon endpoint: Forget it…
On the other side the display from the Lumin streamer are very small, but the system rock stable.
Matrix Audio had in the newer xx2 items very good (much better than before) displays, but not very large. Ideal for using as desktop streamers.
Naim has larger displays, but not used perfectly.