powerd taking more than 100% of CPU seems to be fixed in today's public beta update of Ventura... 13.0 Beta (22A5331f) Yay! I'll reboot just to be sure.

WebGPU support has been turned off sometime around Safari Tech Preview 100. My team is also waiting to see when WebGPU will be brought back to WebKit. https://webkit.org/blog/9528/webgpu-and-wsl-in-safari/