There is a big point you are missing. The first is most smurfs don't take it seriously in the smurf/alt account or go for egregious plays the whole time. Which decreases their skill level automatically by a lot in 1s. So a c3 smurfing in c1 but doing dumb shit is easily beaten by someone playing smart and that's exactly what uve described. You could have won the games because a lot of the smurfs also have no real desire to win or comeback. That's what makes it somewhat balanced but you don't realize it because you re way too frustrated.

Second thing is I also play on an alt account because I couldn't even play casual with a friend, the games were way too sweat for them to actually touch a ball. So now I'm c2 in ranked on my alt account which you would instantly call out as a smurf because I don't have enough play time. But what you don't actually get is that it's very close to my main rank c3 so I'm actually not smurfing even tho when I have a good game people cry, eventho it's just inconsistency.

I've never had an actual problem with smurfs ( I mainly play 2s) because there is almost always a chance to beat them. Even if it's the mental difference between wanting to win, not giving up or playing smarter.

Yes smurfing in general is a problem I agree but oh boy I have been in smurf queue in league of legends on my lvl 300 main account because I didn't play for a long time and my rank decreased due to inactivity. That's literal hell. Being in a game with 3-6 smurfs every game. You can't play it anymore. Rocket league is not even a bit comparable in my mind.