As I saw in a youtube video (that I won't be able to find again), no.
If you sell your game through Steam, you cannot have it cheaper anywhere else. Even DRM free version on your website. Even temporary sales.
I suppose there are some sort of exception for bundles since you technically do not sell the same psckage when bundled with someone else.
Otherwise games would be cheaper on GOG, Itch, ... that take a smaller cut.
Do "foundational changes" mean they will play games on WSL hoping the "hyperV, WSL(inux), proton, game, WSLg (Wayland)" chain will have less slowdown than the "Windows, game, directX" route?
At least if they do it performance will stay on par with SteamOS as long as hyperV doesn't bloat too much.