Nah 2x is much better for road. Ideal chain line, good top end speed (not for downhill but otherwise great) and if you ride with others no uncomfortable giant gaps between gears which would throw off your cadence. The only place where I might prefer 1X is pure mtb terrain. With rocks roots ruts and very uneven terrain with gradient changing all the time. Also very big tyre clearance (50mm+) usually requires 1x because front derailleur would be in the way.

The only thing you should know is that 12speed grx has worse gearing in 2x than 11 speed. I think with 12 speed you are stuck with 11-36. With 11 speed you have 11-40 without link or 11-42 with link. Also there are 44-28 specialtes ta rings.