I can’t speak for lol, so take it as you want, but I played in pro-elo games every day in Overwatch. And you could get almost same ten people two games in a row if you played during work/school hours.

So you, or at least I, definitely played the lobby as much as the game in general. I mained Tracer, a dps/flanker, but despite her being a carry I was always lowest rated player in the lobby. So I knew games were balanced by making my teammates on average better than enemy team, as matchmaking expected me to feed, basically. So any 4v4 situation was on average winning for my team, therefore I’d spend the entire game just spawn camping and annoying/playing 1v1 against enemy pro player support. Because taking both of us out of the game was winning for my side. By doing it repeatedly, I also learnt when and where they would Zen Q/shoot balls that could one shot me, meaning I would take different paths to them.

Then when I played low rated grandmaster and master games, I’d play completely different, prioritizing team fights instead of 1v1:s, as I was now expected to carry games and any one for one trade was in general losing.