Again, I know no C++ and a very limited amount of C, so don’t put to much value in my comment. You seem to be very fond of switch statements, consider not stuffing to much code into each case. It make the flow hard to follow. Break the case code into functions and call those.
You have a switch with 40 cases, to load the SPIR-V. I feel like there’s a better way to deal with that. Maybe just a strict naming convention, so having the ID is enough to locate the file.
Impressive work in anycase.