MAM bottles and Teats

From birth I’ve introduced the bottle to my little girl. We had her on number 2 teat since November but we were finding it as if she was not drinking properly from it. She would have like 1 or 2 oz of formula and spit the bottle out. I’m also BF her and she was just reaching for my boobs instead of her bottle. For the past two weeks I was finding it difficult to BF and just mainly tried to give her a bottle but it was like she wasn’t drinking and just spitting everything out. I watched a video on Instagram from another mum who kind of had the same situation and she went to teat X. Ordered some from boots and tried it out but that flow seems so fast and it’s just going all over the place. She’s literally wasting her milk at this point. Not sure what I’m doing wrong here, shall I keep her on teat 2 or take her back down to 1 but then potentially she will be working harder to drink. Can I just say also she’s got a bit of a cold and stuffy nose too so not sure if that’s impacting it too.