Not sure why you think this would have a significant cost to render. If you can run it on your PC in realtime you definitely can render it on the same hardware. Content for render and for real-time is two completely different things. It’s a lot of additional work to make it VR/RT. For rendering you make content only for the parts which will be seen on camera. You don’t care about unwrapping your models and polygon budget. You can render in multiple layers at the same time and tune everything in post production. Technical high-poly modelling is way simpler and cheaper than low poly, which you are going to need to have decent frame rate. You are not locked into a single machine and can rent render farm for exactly as much time as needed. Should I go on?