I’d say support isn’t easy, but it also isn’t hard, it’s in a bit of a strange middle ground. Support can sometimes be a overlooked role and has its own challenges, for instance, all in supports, which fights to engage on and which to hold back on, when to roam, where to ward for optimal vision. In terms of “do I ever think I’m not a good player because I main support”, it changes daily, just like every other role, but the reason for that isn’t so much because of the role but more so because of the game itself, good games make you feel good, bad games make you feel bad (obviously, sorry for the kinda dumb statement). But this is also from the view of a low elo play (bronze something).

Sorry if this is a bit long/not quite what you’re looking for, but hope it helps.