Made a reddit post about this and I linked it to a dev and he said I should make a forum post as well so here I am.
So Basically I think its insanely harsh how you get so little XP if you fail 3 times on co op, especially since I played for an hour. (I've had games that go past this time too) And its crazy since every sandstorm match you play a large chunk of your XP comes from "Time played" after ever match and I've lost tdm matches and got more "time played" XP than when I lose 3 times on Checkpoint so IDK if this is a bug or whatever, seems a bit ridiculous to me.
I mean just look at the screenshot below, its so little XP to be playing the game for a whole hour on one specific map on one specific mode. It just doesn't feel very rewarding to the player after trying to attempt to win 3 times. I mean I tried my hardest but during the free weekend alot of newbies had no clue and I didnt want to leave because then I'd get nothing so I tried to help them but ultimately they didn't really play the objective so we lost 3 times.
A lot of people seem to agree with me on the reddit thread as well, please NWI look into this!