Aliexpress has a sale from Apr15 to Apr20, so you may have luck with farsports or elite wheels, for example. Other than that, peter from carbon speed, whom you can find on the forum (petercycles@foxmail, i think? - do a forum search), has good deals. Ditto on Leon from Yuanan (OEM for Elite wheels, also on the forum).
Yes, you would have more comfort with steel spokes because steel is compliant in a way carbon isn't, and sapim cx ray / pillar wing 20 spokes are nice spokes. I can't speak for cheaper ones, i would not cheap out on that.
One thing you dont mention is tyre, tyre width and pressure. If you go wider / put latex tubes vs butyl / put TPU tubes vs butyl / go tubeless / lower pressure, you will also gain in comfort, so you may not have to change wheels. The gold standard in tyres is conti GP5000, if you run crap tyres, that'd likely be your best return on investment.
Power transfer is a vibe that's used to sell bikes so we can identify with Pogacar. A comfortable bike is far more important than optimizing the last watt of power transfer. If your bike hurts you, you'll ride it less, which makes it a bad bike.
