Sweet, was just looking for something like this the other day. My use-case is not for guitar, but just to offload some fx processing out of a DAW - a friend and I have gotten into jamming recently, and while you can do just about any musical production task these days with a budget laptop and enough patience, where you quickly run into limitations is running multiple realtime effects. I'm not yet serious enough about it to start spending $ on effects pedals (which typically cost hundred of $ each), or even to have a clear enough idea of what pedals I would want, but I know enough about electronics to realize most modern ones are just a glorified arduino with a a 500% markup, so a budget-friendly programmable swiss ay knife pedal would be a dream.

For my use-case the touchscreen is entirely unnecessary (programming it via a WebUI sounds more convenient anyway if you don't need to use it sans PC), which is inflating t he BOM by about 500%, and of course RPi4 is a uniquely poor choice of target platform at this particular moment in time, so seeing if it can run on a headless Pi Zero is definitely going on my endless to-do list. ;)