Run Qubes.
Use PassThru for grating a full gaming virtual.
Less issues and hassle for yourself.
Dual booting, if you want a secure system is meaningless.
If you have Windows on one drive, and another drive with Qubes, then Windows can still see Qubes and all the guests. It can see it all.
So saying that you want security, then dual-booting, is pointless.
If you want to dual boot, then have 2 drives. and turn off the ones you don’t want to have used each time you want to switch.
Or else do what I do, hot swap drives.
I unplug my Windows drives and plug in my Qubes drives.
So depending what I’m doing determines what I am plugging in.
But before I plug in my Qubes drives, I do boot to a specific USB drive that clears my RAM and anything in the CPU cache. Along with a few other things that I clean up. But you get the idea.
This maintains my security.
If you are willing to do this, then I see no issue with you having multiple systems running when you need them.
If you want Qubes, then gaming under Qubes, build yourself a gaming HVM.
I see no one has linked it through to you yet.
Here is the link that I have seen that has been linked to other people asking about things.
This should make things better for you, and easier.
It’s actually very very easy to get things going whichever way you go, whether it’s a GPU passthru or installing the OpenGL passthru system for accessing the parent GPU.
So it’s up to you. Gaming under Linux would be better if that’s what you want.
As for doing things with Linux, is easier under Qubes. Linux under Windows is silly. Windows under Linux is smarter. No Windows at all is smartest.
So, for gaming, just use Linux, run WINE or CROSSOVER or any of the things that are based on WINE which allow Windows things to run under Linux, natively.