I am in the process acquiring new gravel bike and idea is assembly it around carbon frame from aliexpress.

https://www.aliexpress.com/item/1005005678330464.html

Carbon frame bottom bracket T47

There is also older version of this frame but with press fir bottom bracket 386
https://www.aliexpress.com/item/1005003550054274.html

From start I was thinking built it with Sensah groupset but two things I do not like: mechanical/hydraulic brake combo and most of the cranksets have aluminium spindle (which can and does brake).
So I opted to GRX400 version with crankset 46/30. Most expensive things are shifters. Hydraulic shifters from Sensah compatible with GRX (PRO HRD) are in similar price range.

Related with wheels I do not want anything fancy and pricy, so something like this:

https://www.bike-discount.de/en/mavic-allroad-disc-6-bolt-shimano-wheelset
https://www.bike-discount.de/en/shimano-wh-rs171-700c-disc-wheelset

I am also open for 1x11 or 1x12 combination but this do not look make big difference in weight/cost benefit.
Created sheet with some cost, weight calculations:

https://docs.google.com/spreadsheets/d/16-dTMKSiL2U5Tx5mPYT0-pqItaRaxRPl/edit#gid=1411140364