Finding Blueprint tips? Or Do I just have bad luck

Pretty new player. For awhile I have been focusing on getting all my benches to level 2, doing quests, ect. I also have been hunting for room keys and saving them up. Recently I have been doing night raid/cold snap events with my keys. I was under the impression this was the best way to get high tier loot. and... sort of?

My stash is loaded with blue and purple weapons and grenades. I still have not found blueprints. In total in my entire 25 hours I have found one weapon blueprint (il toro) and like 3 grenade bp. I am talking dam control tower and buried city hall at night, both twice now, and no bps (I do have like 3 bobcats and 3 tempests, so can't complain too much). I have tried running to raider stashes but this hasn't yieled anything either. I see people here talking about getting 2-3 blueprints in a run and wonder what I am doing wrong.

I want to make a push for the level 3 benches, but I would really love to actually have something to craft when I get those. Thanks for any advice!