Some of this was just discussed in this post but I’ll try and give an answer to your best approach (IMHO) and hopefully others including @wizard will chime in.
First of all, with 2880 lights, you’ll perhaps want to do multiple outputs (output expander) or even multiple PBs, depending greatly on the pattern complexity. It might be fine, or the frame rate might be slow. All depends on the pattern difficulty.
As for knobs and buttons, for pattern changing, I believe the built-in button (which you can wire in parallel to, to your own button) is the only way to change pattern, we don’t have an in-code method otherwise (yet). Nor “global code”. You can hook up some physical controls to replace a slider, or simulate a knob, and perhaps multiples depending on the pins available…
Yes, using websockets, you can externally control the PB, in the way you describe. You’re building a panel simulator then essentially just sending the results to the PB. That is likely the most functionality method. I could imagine using the sensor board interface for example but it would be half a solution probably at best.
Perhaps these items will rise toward the top of the development ToDo list, if the (few?) people asking reflects a big need, compared to other competing for time/energy development improvements requested. We have multiple threads of these requests already. Consolidating them and ranking them might be the next step.
But I know Ben has lots already queued up already.