We’ve also switched from MAM to Lansinoh teat. They fit in the MAM bottles so you don’t need buy all new. We have mixed success but I think that’s the trouble with combi-feeding. Some nights she’ll take it and others she will get so worked up
Ours gets on with tommee tippee bottles and I’ll also turn her in slightly so she’s in the position she would be for breastfeeding. Seems to do the trick rather than her being flat or very upright
i had the same issue with my 15 week old - tried like 6 different bottles - spoke with an infant feeding specialist who suggested giving the baby the teat to play with and suck when they're happy to get them familiar and comfortable with it (that didnt really work for us but might work for you) she also sent me this to read: https://www.rachelobrienibclc.com/blog/bottles-for-breastfed-babies-introducing-a-bottle-part-1/ after reading this we tried the lansinoh bottles, size 2 teats - it did take alot of persistence and different positions from my husband, making sure the milk was warm enough, giving it to her at different times of the day to get her into the habit - and she does now take it in small amounts, 60-80ml (mostly - there's the odd day where she throws a strop and refuses but on the whole we've had most success with this one!)