The official stance from Wyze is that you can’t use the WCO while plugged in, but that’s only because you have to remove the weatherproof seal to plug it in. It’s perfectly capable of running while plugged in.
I’ve charged my WCO a couple times from a 28W foldable solar panel (RAVPower I think) I got on Amazon a while ago. It’s not a permanent solar panel, but I suppose if you had a weatherproof solar panel with USB output you could set it up semi-permanently. Just seal the USB cable into the back of the WCO with some clear silicone and it’s now a powered weatherproof WCO.