If you are stuck to Windows there are some 3rd party efforts like https://github.com/ddeverill/SteamlessController
The last generation of steam controller still had a mode you could start it in where it would register as xinput device. Seems that's gone on the new generation.
Yes? What's wrong with that? Then it's at least usable.
Can you hack it together in theory, get something working but making sacrifices left and right? Sure. But why would Valve want to do that? Use experience would be incredibly bad.
But give it time. There will be a standalone driver for Windows eventually, either from Valve or from the community.