Hmm, actually, it is and it is not.
It depends from the interaction between the guest OS, the host OS, the drivers in the guest OS, and Ren'py (or any game engine, for what matters).
I have not looked at it in the last +/- couple of years, but that was one advantage a commercial product like VMware had in the past, that it allowed direct GPU access for e.g. CUDA acceleration even from gues VMs (basically, "exposing" the hardware to the guest OS). As far as I know, even other virtualisation solutions have advanced in that aspect, I know even the WLS 2 from MS now allows direct access to the GPU (though that is the opposite direction, a bit of Linux on a Windows platform, and I did not try it, so I cannot say how good it is).
Additionally, under linux, also as host, you may have to see if you are using the drivers from the distribution, or the NVIDIA driver (noticed I am referring to NVIDIA, but I know there may be issues even with ATI cards sometime) - that can also have an impact.
Ren'py is not ML
, but it is based on python, so it may also have an impact, depending on what libraries and call it tries to use under Windows - though I don't know enough (I don't have enough information about) the inner working of Ren'py to say anything more, sorry.