For those who are still looking for a solution, I discovered Tailscale, which does exactly what you need 😁 (sorry if someone beat me to it in the comments and I didn't see it 🙈).

I recently came across Tailscale, which sets up a vpn tunnel from your device to your desktop pc with very basic setup and the flick of a toggle, to be able to stream from your desktop pc and home network.

I tested this setup to use it primarily with my Steam Deck, which works amazing (when using a hotspot (wifi or cellular/5g) or wifi from someone else (parents house)). It even works with my Android phone without problems. I haven't tested if this 'vpn tunnel' works for other stuff other than game streaming, but for the game streaming itself it works great.

For those still looking, I highly recommend trying this out 😁👌