1x on new bike

1x can absolutely work on the road.

A standard 2x11 actually has 14 distinct useable ratios, so going to Ekar or AXS only loses you 1 or 2 gears. Moreover, of those 14, the top 2 are going to be rarely used by most non-racers. If you don't race/average less than 35kph you just don't need a top gear ratio over 4.5 (at most).

Based on looking at gearcalculator, I worked out that with an Ekar 40/9-36 setup you can hit every 2kph increment between 12 and 50 kph while staying between 85 and 95rpm, and won't spin out until over 60kph. That covers pretty much every eventuality for the vast majority of us. If you want more insurance, then with a 9-42 cassette you can get the same top end and go down to 8 (!) kph at over 85rpm, though you'll have to go to 100rpm a few times to hit other speeds.

But...

1. Smaller rings/cogs and less straight chain lines bring with them efficiency losses, noise, and faster rates of wear. 

2. I'd suggest that 12 gears is a minimum, or the losses at either end and/or the jumps will be a real issue for most.

3. I'm still not sure why you'd want 1x on a pure road bike. Most modern FDs work very well and reliably. I've only gone for Ekar because this is an n=1 build with 2 different wheelsets and cassettes.

I converted my previous commuter to a 1x. When that died, I only considered 1x setups because the bigger gaps are less annoying than a front mech (which I fully accept may relate more to my mechanical ability than anything, because the 105 mech on my 2x road bike is tolerable - I could never get anything cheaper to work nicely).

I have a 40 up front and 11-30something at the back. On the flat, never wish for anything more (that said, I only commute and I'm very content not to race); downhill sometimes I can't get my cadence high enough comfortably. Only ever use the big ring at the back when I'm towing the little one in the bike trailer up the hill home from nursery.

Personally, I'd be very happy with a 1x road bike if such a thing exists when my current one moves on. I guess a lot depends on how sensitive to cadence you are - I mainly run for sport and ride for transport these days, and don't mind a cadence anywhere between 70-90rpm. Perhaps if I cycled as a main sport, was better with a wrench (and maybe smoother shifting) I'd prefer the choice on a 2x.

I converted my 1x gravel bike to a winter road bike after COVID stopped my towpath commute and whilst it's ok, I definitely prefer a 2x setup for road riding. I find I just can't find the right gear. It's shimano grx with a 40 on the front and 11-42 on the back. 

Hi Fost, like you I did all of the calculations and I tried a x1 setup which covered my usual gear range, it stayed on the bike for about 6 months, I tried very hard to like it but the jump between the gears (even riding on my own at my own speed) was too much, I never seemed to be in the right gear.  For me the jump between gears is mportant and I now ride my old set up of 34/50 with a Miche 11 speed cassette of 13-27 (summer bike) or 13-28 (winter/tourig bikes).

Unless you're doing paceline or racing, do you need 44*10 often? For my everything bike I moved to 42*11-42 to give me enough top speed and enough climbing. When pushing on I hit top gear on the flat, but not that often - any faster downhill is freewheeling for me. 42*11 @90rpm is 27mph, 44*10 is 31mph.

My fast bike is 48*10

Have a look at the speeds you normally pedal hard at, and pick the gearing to suit.

When I had 1x I found it perfectly usable on the mostly (but not all) flat commute and riding solo. The gaps can be big and this is the main drawback - when riding with others I often found I was in the wrong gear / wrong cadence etc. When you don't have control of the speed etc then it's not so great...but not terrible especially if most of your rides are solo or easy cruises

Your logic seems sound to me.  If you are not wedded to going electronic Ekar may be worth a look - especially if you'd prefer all the gears on the RHS.