Glad it worked. I was thinking about getting and 8GB Pi 4 and using RAM disk.
I found my original VMs as virtual box. This has the cross compiler setup so much faster than Pi.
Don’t forget the gotcha when opening panels – the Linux meds something unticked.
My mate loaned me his touch screen and it worked well. I met a YT via K1 posts – he has a Linux tablet that runs Ctrlr. I sure would love a powerful tablet so that I could also run ZynAddSubFX – Pi doenwt quite run it fast enough
Anyhow glad you got it to build – I found I used the debugger to get to learn more about the internals of Ctrlr.