Hey mama,
Hmmm, would you like to try a different flow for the teat? It could be milk is rushing into her mouth and she can’t control the milk flow so she’s getting frustrated.
Another way is to allow the teat to slip into her mouth rather than shoving it in, then feed her in an upright position so that she is in control of how much milk she takes. Another method to mimic breastfeeding (if you do directly latch or nurse) is paced bottle feeding. You can read more about it here:
https://kellymom.com/bf/pumpingmoms/feeding-tools/bottle-feeding/
https://www.mamanatural.com/paced-bottle-feeding/