I think this is a really important point. Solo RTS is very engaging even if you actually suck at it. The layers of complexity required to be good are basically unfathomable unless you grind against competitive players and understand the various local maxima of the metas.

Competitive RTS is very stressful. I would say, more stressful than other competitive games as mistakes, or rather, the absence of great moves, compounds quickly into a disadvantage.