So Team1:
This is a 4 stack+1rando.
Team2:
This has a duo and 3 randos.
Team1 has mmr disadvantage due to party size. Parties are matched against higher mmr ppl for fairness.
That’s why Team 2 has Plats and fewer Silvers.
You didn’t specify which team you were.
The usual gain/loss is 200 points. The extra 22 loss indicates that this was not the first lose, and that your team probably was the favoured one (the one expected to win).