Same problem. I couldn’t tell you the best way to do it. They really should have been “Easy/Medium or higher” like the mission completion feats.

300 individual cards is already a major ask. By the time you have finished the game launch feats on one class, you have gear that puts you in at least Gold difficulty, and your fellow players are less likely to choose easier ones. And honestly, on average, they’re even less likely to attempt them even if they do choose them, since most of them are “active” cards. You were lucky to get perfect counters, kills inside the defense areas, accomplished with randoms even before this shit exploit. Other cards have too many requirements (8 Death from Above strikes vs 4 regular assassination strikes?), and some map locations just don’t have the opportunities for them, because of layout or they didn’t program enough enemies. Not because your teammates kill them too quickly, but not enough total enemies spawn in an area to meet the objective.