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/

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.