I have been using Spectr with all available pipewire-jack apps installed from the Void repo.
It performs wonderfully. I generally run the jack buffer at 256 with cpu governor on performance. Great snappy response and highly stable.
I open the Calf Plugin rack and use virtual instrument plugins, in particular Fluidsynth, which plays sf2 files. Over the years I've downloaded every available free sf2 library I could find. I have a 40GB library including those and also sfz, and other multi-sample formats, but sf2's sound nice, the better ones are pretty expressive, and they are low resource and stable, unlike some very buggy multi-sample formats, which are very resource intensive and not nearly as stable.
Then I open the carla rack on another workspace and use its connection graph to route midi and audio streams. I save the configuration so I can simply open a file and have the connections made.
Spectr is extremely well suited for this kind of thing, being that you never have to resize windows, The wm is very low resource, and stable. So it's easy to open whatever you play and use, each on it's own work space opened to the entire workspace, and then switch from one application to the other simply by using Meta+[0-9]
So it limits having to grab the mouse when you're trying to make music.
The other cool thing is when the application opens a separate menu, they don't overlap the main window, and both are spread evenly across the screen and can be resized with keystrokes. Mine being Meta+H or Meta+L
Very enjoyable. I'll be playing a virtual synth at a rehearsal tonight, so I'll followup.
That's my report!
Excellent reports. Exactly why we pressed forward to assemble this system. The performance is spectacular from the first builds.