I’m not going to watch the video, but what’s the procedure for switching between Linux and Windows? Usually you dedicate a GPU entirely to VFIO, with a 2nd GPU for the host OS (or run headless).
Anyway, will it work? Yes, minus some anti-cheat software. Will it be a simple solution? Well, once you get things stable, yes. The tech behind this is mature, but it can be a rabbit hole.
I would look into a non-Nvidia GPU for your 2nd PCIe x16 slot (x4, shared with the 2nd M.2 slot FYI). Good idea to check IOMMU groups before buying anything, but modern AMD motherboards are usually fine. Blacklist the Nvidia drivers and dedicate the 3070 to VFIO to make your life easier, and run Linux off the secondary GPU. Intel A380 might be a good choice. Do gaming stuff on Windows and stream via Parsec/Looking Glass/Moonlight+Sunshine; everything else on Linux.
DATA: I am puzzled, captain. This joke did not receive a single humorous reaction. However, I calculated with 99.987625% certainty that -
PICARD: Well, Data, there’s more to humor than, well, data.