I have a Raspberry Pi that runs pihole and Wireguard exclusively. My home server is a Kubernetes cluster running on an old desktop PC and 2 Intel NUCs.

The reason for the separate Pi was essentially because I only had the desktop PC initially, and for a while I had a faulty CPU, making the desktop PC crash or become unresponsive, so it helped a lot having DNS and VPN access separated from the instability.

Start watching the second hand market. Most of my PC components are bought second hand, and at much cheaper than buying any of those components new.

None of these components are of course bleeding edge, but still sufficient to play any game I want.

I bought an AMD Radeon RX 5700 XT this summer for 1000 DKK (~€133 or ~$157).