The USB3 port was a really exciting feature of the Pi4 release, but without USB booting support they are pretty well useless for RACHEL-Pi. The current official RACHEL code base doesn’t have USB module loading support and all of the images that I have released so far have just been getting the official code working with the latest operating systems/devices.
I have developed USB module loading separately from that code base as well as other features, modules, UI updates, and admin interface changes. USB module loading works in my testing with Pi4 and the USB3 ports, but I’m not really sure how to proceed. Anything I release at this point isn’t part of the official RACHEL code, but the official code hasn’t really changed so any new official images will basically be the same.