It seems the VR device "Pico 4" is not supported.

[YLyeliang]

As the title described, any solutions to resolve this?

[YoDudeNoWay]

Here's what I did to make it work on mine:

• I unplugged my Series X controller from the PC
• Deleted all \common\Subnautica files, including BepInEx and SubmersedVR
• Reinstalled BepInEx through Vortex instead of dropping the files in the main Subnautica folder like I had done previously
• Reinstalled SubVR by dropping the files in the main folder like you usually do
• Don't forget -vrmode and openvr on the launch options

And that's the fix I encountered. I don't really know if it was fresh install that did the trick or just unplugging the controller from the computer, since i'd launch Subnautica and it'd load the standard VR port, which uses the controller. I still could join a save by using Pico 4's controllers just fine, but the other buttons such as the joysticks wouldn't work. Maybe it was a conflict that was caused by the controller being plugged in? Anyway, it works just fine now. Hope that helps!

[NeonPixels]

I use the Pico 4 through SteamVR, and it worked perfectly on the first try.

This might mean there's some configuration issue on your end. Sorry to not be of much help, but I wanted to mention that it has worked correctly in my case.