Back in the day, I was very interested in (the now extinct) PC-BSD, but it really didn't like the unusual HDD setup I had (Third IDE channel maybe? The details are fuzzy now.)
Never got to the stage of trying gaming on it, but I think I might have been planning to dual boot?
Anyway, it must have been a while ago because that was my previous PC, which I donated to a relative the better part of a decade ago.
So, given that it was a FreeBSD, I guess that's what I'd be looking into, but I can't say I know enough right now.