I ordered a 5.5x2.1mm on Amazon (link) and it was too big to fit. So weird. I had to revert to plug power.

I have one of these. It looks sketchy but it seems to work ok.

* Argh... it only outputs 12V 1A, you need 3A.

You could get one of these to get power to it via ethernet. I saw someone on the Facebook group mention that recently.

I'm testing one as well, and I agree with everything you said... I love the build quality and how secure it is.