I suspect you can relatively easily obtain a completely deterministic machine by running QEMU in 100% emulation mode in one thread. But what you are after is controlled deterministic execution, and it's far harder. That is, making your multiple processes to follow a specific dance that triggers an interesting condition must be very involved, when seen from the level as low as CPU and OS scheduler. Hence a language-agnostic setup is hard to achieve and especially hard to make it do your bidding. It may drown you in irrelevant details.

I once built a much, much simpler thing that allowed to run multiple JVM threads in a particular kind of lockstep, by stubbing and controlling I/O operations and the advance of the system time. With that, I could run several asynchronously connected components in particular interaction patterns, including not just different thread activation order but also I/O failures, retries, etc. It was manageable, and it helped uncover a couple of nasty bugs before the code ever ran in prod.

But that was only possible because I went with drastic simplifications, controlling not the whole system but only particular synchronization points. It won't detect a generic data race where explicit synchronization would be just forgotten.