Coulson is proud of the Avengers, he really is. Of course he is. Phil had his hand at putting the team together, made the arrangements, did the research. And they did what they were meant to do.
What he cant.
Because agents like Phil arent genius billionaires. Or demi-gods. Or even iconic American heroes.
Phil isnt jealous. But it does hurt, to know how easily an agent like him can be replaced in the field of battle. Even if we arent technically soldiers.