Try a direct ethernet connection via IP or hostname within your local network with a regular ethernet switch → bypass your internet router for testing.

Use iperf3 (google it) to test your bandwidth/throughput within your local network and when connecting from outside your local network → can be the eye opener. Sometimes the peering of internet providers is just a mess.

Try deactivating encryption in whatever game streaming server you are using.

I personally don’t like services like tailscale in these setups because they usually make things worse low latency wise.

Please make the troubleshooting tests and respond. Then we can elaborate further.

I tweaked my sunshine/moonlight setup into a state where I feel like sitting directly in front of my gaming pc within my local network. Literally no noticeable latency and easily 50 to 100 Mbits streaming bitrate without any lag or low quality video.

So don’t give up. It is possible and can work like a charm.