Help? Flat nipple? Struggling.

I’m looking for advice because I’m feeling really discouraged as a FTM..

My daughter is just over 2 weeks old. She was born at 5 lb 15 oz and weighed 7 lb today, so she’s gaining great on pumped breast milk. I produce enough milk (around 25-30 oz/day), but my goal has always been to nurse directly.
We’ve been seeing an IBCLC 2-3 times a week since birth. She has no tongue tie or lip tie, and we’ve tried different positions, skin-to-skin, breast compressions, and a nipple shield because I have flattish nipples.
Our biggest issue is that she won’t open her mouth wide enough. Even with the nipple shield, she latches onto the tip and gradually lets it slip out until she’s barely on it. If I try to get a deeper latch, she gets frustrated and starts crying. I feel like I’m constantly forcing the latch instead of it happening naturally.

I’m exhausted from pumping around the clock and honestly heartbroken that we’re still struggling despite so much lactation support. I feel like we aren’t making much progress.

Has anyone had a baby who eventually learned to open wider and latch deeply? Did they simply get better with age, or was there something specific that helped? Or any professional able to give some advice? I’m feeling really frustrated, sad, and overwhelmed, and like I’m failing / not connecting enough with her because she doesn’t latch and I spend most of my time pumping and doing bottles.