This is similar to what I do. I have an old pixel 3xl and a Sunshine server running on my gaming PC. Moonlight is installed on the Pixel and I stream my games to it from the PC. I have a WireGuard VPN setup for when I am outside the house. It works very well!
Edit: Inside the house, I have a Rasbery Pi 5 with Libreelec installed which has a Moonlight addon as well for when I want to play on my big screen TV.