I would try a custom request with wide rims in whatever depth you prefer (>24mm internally is best for gravel tyres), ratchet hubs (they're basically all copies of DT Swiss) and Pillar Wing 20 spokes. Yuan An, Serenade, XMCarbonSpeed, etc.
Expect to pay $500-600USD including shipping.
It seems like not many of the budget vendors offer wheels without spoke holes.
At the moment I'm looking at trying to find some wide options given the positive reviews of the new Zipps. XMCarbonSpeed offer a 28mm int / 36mm ext rim, but only in 50mm depth at the moment:
https://xmcarbonspeed.com/Productinfo.asp?f=1650They also offer some smaller depths in a 26/33 width profile.
On AliExpress, Easedon seem to offer some rims in a wide profile with 30mm internal / 36mm external in 35, 40 and 45mm depths:
https://www.aliexpress.com/item/1005006549308069.htmlOnly seems like rims only at the moment but perhaps if you ask they could do a build with the Goldix hubs they offer on other wheels?