Did you note the day of the week counters. One of them was only Thursday and Friday and the other was spread out over multuiple days. But that's likely to be the result of not using the double accounts in every game.
It's a massive GD red flag to join a 2x2 with a p who has gone 0-19. You should never do that. Best case he's a horrendus Wl player, worst case he's a plant. Either way don't play with him.
I agree that account was suspicious as hell. It's hard to be that bad and few people have the patience to lose 19 straight.
I've had people join my game on a 3x3 on my team, just to make me lose. Attaking his own team mates. Often they don't even try to hide it. But you can't know if his is just trying to make my side lose or if he is also on the other team.
I just use my Black list more often these days
Even Better I joined a game where someone made the boot times "never" and then when he appeard to be losing, he never played again. He is still an active member because i see him playing in other games. Still that game is sitting there for nearly 200 days