This is more of an Ableton tip than a Polybrute-specific one, but I'm leaving it here in case anyone else is tearing their hair out trying to figure out why Polybrute Connect VST won't work properly in Ableton Live 11 (on Windows 11).
No matter what I tried, I could not get the knobs on the Polybrute to turn the knobs in the Polybrute Connect VST on screen. After a couple of hours of frustration, I realized I was using the VST3 version of Polybrute Connect and remembered having a very similar issue with the VST for another hardware synth (OB-6) that was fixed by switching from the VST3 to the VST2. So I tried using the Polybrute Connect VST2 and everything immediately started working, knobs and all.
Since this has happened with two synths from two different manufacturers, I can only conclude that Ableton Live's implementation of VST3 must be buggy, at least for plugins that interface with hardware synths. Stick to VST2 and you will have an easier time.