Not adding much to the debate but even though I'm a committed 1x user I'd say firmly "it depends on the rider" and if I was doing your riding I think I'd be on 2x.
For me the advantages of 1x aren't so much because front mech setup is a problem (It's nice not to have it but I don't think it really is a problem per se). They're more around the dramatic improvement in chain retention, freeing up the left hand for a dropper only, and getting rid of stuff off the bike. Probably those things don't matter on the bike you describe?
Off-road I'm firmly in the camp that starts with 1x12 as the default setting, and you'd have to go a long way to persuade me that something else is better for the riding I do . But my roadie is 2x9 I think, and my commuter is 1x7 because it's pancake flat. There's literally a gear system for every situation, just play about until you get the spread you need.
If you've been away a really long time then the big change would be a clutched mech. Other than that I'd just run what you've got as long as the gear range is what you need. Recently moved up to 12 from 10 speed on full suss and was amazed how heavy all the parts were, that's a whole lot of unsprung mass, but on a frame that has to be 1x it is worth it. OTOH I still have 3x10 on my hardtail because I've seen no reason to replace it
My 15 year old road bike is 2x10 with an 11-26 cassette (IIRC). I absolutely love the close ratio block as when pushing hard on the road I can really feel big jumps between gears. However I hate the double as I tend to spend a lot of time on either the big ring and bottom half of cassette, or small ring and top half of cassette. This means lots of trimming on the front mech, and occasional chain drops if I change chainring while on the wrong end of the cassette. First world problem but a real pain sometimes.
A couple of weeks ago I bought a Cervelo Aspero gravel bike with 1x12, to replace the road bike but give me some off-road options as/when I fancy it. It’s got a 36T chainring and 10-36 cassette. I spent months worrying about going 1x on the road but actually it’s been pretty good, I do notice the jump between gears but it’s not as bad as I thought it would be (MTB background almost certainly helps) and not worrying about trimming the front is wonderful. I’ll top out at about 30mph but I only ever get there going downhill so not bothered, 25mph on the flat is my top top end and that’s still achievable. 36T - 36T is fine for the ups, in fact is probably a bit lower than my road bike goes.
I do find that on the road I spend most of my time in gears 7 or 8 (AXS app does a ride report with gearing etc), not that that is a problem. I’ve done a couple of decent gravel rides in the last week too and gearing was spot on, most time spent in the middle of the block.
I’d still much prefer 2x for road to get the close ratio gearing, but for me 1x is a great compromise.
Have you seen the Classified Power Shift system? Could be the best of both worlds if you are building a bike and have cash to burn:
https://www.classified-cycling.cc/
I personally found 1x11 too limiting. Where I ride locally is flat so I only used the last three rings but when I got to the mountains the big rings weren't big enough to get up the steep stuff. I changed to 2x11 with a Shimano DI2 XT shifters and mechs and am much happier (I use the syncro-shift function which automatically changes between front rings), though I would be happyto change to 1x12 if buying a new bike.
Always 2x for any serious road riding. As above, you'll never find the right chainring/cassette size for a comfortable range of gears at a normal cadence for all conditions - you'll either be spinning out of grinding. Chainline will be crap and it'll likely be heavier.
Sram pushed 1x so much because their cable front Mechs were awful, in part down to their Double-Tap shifters that prevented you from overshifting if needed. Aquablue spent one ill-fated road season on Sram 1x, and it became a hushed up PR disaster will the riders publicly saying how shit it was.
50x34 with 11-32 will get most people along, up and over pretty much any road terrain. 50x11 at 90 rpm will see you zipping along the flat/downhill at over 50 kph. 34x32 will get you up Alp d'Huez.
Sram pushed 1x so much because their cable front Mechs were awful
I think full suss 29ers pushed the development of 1x systems more than anything else really. If you remove the front mech, loads of options are opened to you for packaging everything a bit better in the BB area, including having a wheel with a bigger diameter. Shock placement, linkages, tube shapes...everything and anything now possible if you take away the need for a mech that has to be placed "just so"
SRAM front mechs were bad though, I'll give you that.
I don't ride on the road much, but if I did then I think I'd go 2x purely for the smaller jumps between gears giving more options to find the better cadence. For MTBing 1x is perfect for me, but not all 1x is equal: swapped from 11-46t SLX to 10-42t SRAM 11-sp cassette on one bike and the ratio gaps are much nicer at the top end of the cassette. No longer have the big jump from the granny gear to gear 2 that existed on the SLX, meaning gear 2 is much more useble now
Do pro racers use the dinner plate rear cassettes? Just a question as I am getting on a bit now and still quite happily run 1x10 or 9 with a 11/38 and 36 front ring.
Personally for me anything greater than 9 is just extra weight and marketing. Last time I had to get off and push was the quarry switchbacks at honister but that was a long time ago.
