Hi @jakec and welcome,
There are a lot of topics about freezing GUI’s and there are a lot of different reasons for it to happen.
There are situations where IOWait that stalled everything, where the power supply was the issue (not likely in your case I guess) and also issues with USB3 interference.
My first guess would be that your hardware is heavily loaded. Second guess, file corruption (mainly noticed where SDCards are used, but still). A fresh install and restore of config might solve it. Since you use a VM, you might just want to run a second one that is as clean as possible, just to see if it freezes.