BF positioning help?

My baby is almost 3 weeks old and we struggle with nursing. He had a tongue tie that was clipped over a week ago and I think it helped a little but it feels like a lot of his latching issues stem from getting him positioned well. I’m larger chested and I try both cross cradle and football holds but it’s a hit or miss every time. He gets super angry trying to latch on and then when he finally does, he falls asleep or just lays there staring at me. Has anyone else dealt with something similar? I use a Boppy pillow for support but it tends to slide out from under me as we use it.