I am sorry this isn’t the enlightening solution, but I am missing some info.
When you say standard ergonomic layout, what are you thinking of? Because that word and the 100% wish make me think of the old wavey looking Microsoft keyboard.
I personally can’t recall seeing USB passthrough on any of the ergonomic boards, and after a bit of looking into the standard I can very well understand why. I have literally never seen audio jack passthrough, not even on standard slab keyboards. So for both these features, why do you want them? If it is because your PC backside is awkward to access, maybe a cable can do the job too?
If you do have a budget besides „it will cost what it costs“, what is it?
As someone that was diehard num pad user and believed it is essential, I am now very happy with a Moonlander and num pad on a layer. Depending on how much you mix numbers and letters, that might not be for you though.