You can surrender only if one player leaves the match and your team is weakened. The player, who left the match will keep only the changes for his ELO points till he left. ... That means, if on player leaves, remaining 4 players gain more points for round wins and the enemy team loses more points for round loses.

Does surrendering in CSGO count as 2 losses?

If you surrender early enough in the match, nobody loses or gains any elo points. The match is effectively deemed cancelled, just as it would be if a player failed to join in the warmup. If you surrender late (after half time) it's basically the same as any other loss.

Do you lose more SR If you surrender?

From my experience it does not make a difference.