I have no idea. It took me some messing around to figure out what my problem was. The Deck’s AC adapter has enough juice for all that at 45W, but the port itself doesn’t seem to output enough. I don’t know about the official dock, but the one I use doesn’t power the other ports directly, it only outputs to the USB-C.
Is there anything else going on in the background? Is something else using up your drives or CPU/GPU time?
I’ve been exclusively on Linux for a while, and I know shader caching happens, but I’ve never noticed it happening. AFAIK it should be very quick and seamless for the most part.
Are you perhaps using the Flatpak version of Steam?
The -W and -H are the resolution you want to display at, so you want those to be your monitor’s native resolution. They default to 1280 x 720 if you don’t specify.
The -w and -h specify what resolution to render at, and are only really useful if using DLSS or FSR for scaling. Skip them if you’re not using that.