Despite all this, a 1× system has always possessed undeniable advantages over 2×. By ditching the front derailleur and a chainring, a 1× groupset can be lighter, and a bike should perform (marginally) better aerodynamically.

Generally speaking, a 2X drivetrain will have capacity for a wider gear range. That is, it's climbing gears will make for easier climbing, and its descending gears will make for less of a “spun out” experience on a steep, fast descent. With less gears, 1X tends to sacrifices a bit of end-range gears capability.

I'm using 1x12 40x10 for gravel and I absolutely love the 1x and I wouldn't go back to a 2x but if was going to ride exclusively on road, I would ride a 2x for sure. You will find the right cadence with a narrower cassette and two chainrings, that's undeniable. For top speed, a 40x10 is 90% enough.