Phono Stage Pass XP 15 VS Aesthetix Rhea

I would choose the Herron VTPH-2 over either of those two. I know you didn't ask for other manufacturer's.

Very different products. One is tube, one is solid state. I would choose based on that.

Both are good, but I would probably select the Pass in your case to stay with the Pass house sound that you like, based on your current equipment choices.

I have a Rhea and think it is great, but system synergy is important as well as selecting what you like in your system.

If it were me, I would go with the Rhea. But that's me. You may not feel the same way. One thing you can do to help choose is to listen to your Wadia connected directly to your amp, and then try it with your XP-20. If you like your system better with your current preamp in the chain, the Pass may be a safe choice. If not, consider the Rhea.