Most people do 1x wrong imo (hear me out)
Chainring should set the avg speed, the cassette sets the spread to take care of a range. I think people going 34+ in the back to try to make up for it are forcing a 1x in situations that dont make the most sense.
56-11/23 on the tt bike; 54-11/28 for the crit bike. In a race where you avg north of 25mph you’re lowest speed will (hopefully) be close. I’d say at least a 50t, probably a 52 (and even in a 52 I hit the 11 more often than the 25 or 28t, hence the 54t).