I don't have the game go test, although I've been meaning to give it a try...
It sounds to me like it's limited by CPU single-thread performance, which isn't suprising at those frame rates. Looking at overall CPU usage doesn't tell the whole story. It's likely that some threads on your CPU are active 100% of the time.
You may have some headroom on GPU performance, so you could try increasing quality in a way that isn't likely to impact CPU performance. I'm not sure what options the game has, but some good candidates would be: rendering resolution, texture resolution, anisotropic filtering. If you can do that, and it increases GPU use without dropping overall performance, it more or less confirms the CPU bottleneck.
Huh, I've seen .local used for this quite a bit and only just now realised that it's meant for something else.
I've also seen .corp 🤮