I use a single machine with an i7 7700 and this gear including a CUDA GPU, all running Windows 10 in a neighboring room. I run Roon Server and HQP and a monitoring program called Cam on that machine. I can run all filters except xtr at DSD 512; xtr-2s is fine.
I think you’ve isolated the issue (well done), but I don’t know why my i7 7700 is ok and the sonicT isn’t. Looking back over the linked thread I see I was reporting getting some pops with CUDA off. I would think that separating HQP from Roon would be enough without CUDA.