Hi OP.
My baby was borderline low birth weight and I was put under a lot of pressure to formula feed in the first few days, but I resisted. I also had a C-section which might have delayed my milk coming in slightly.
One thing I did was I started expressing colostrum at around 36 weeks and I had some syringes of colostrum in the freezer. I supplemented my baby's feeds with extra colostrum in the early days.
My advice would be not to miss a breastfeed in the early weeks if you want it to work. Supplementing with formula can interfere with establishing your supply.
I would recommend getting a Haakaa, and once you get to about 3 or 4 weeks postpartum, try using the Haakaa on one breast while you feed from the other to catch the extra milk. I recommend getting the Haakaa with the suction lip and the lid, because this makes it easier to store it. You may not get much milk to begin with. If you manage to get around 30-40ml milk, you could try giving it to your baby in a bottle at the beginning of a feed once they are about 4 weeks old, and then once they have drunk the expressed milk you can continue with the breast so you aren't missing a feed.
This worked really well for us because my baby got used to taking a bottle maybe a few times a week from when he was 3 or 4 weeks old. He didn't need to take a bottle very often while I was on maternity leave, but it did come in useful sometimes, like when I needed to leave him with my MIL for a few hours, or when I went to a wedding and wanted to be able to drink more than usual.
I would recommend doing it just enough to let your baby get used to it, but not so much that they start to prefer the bottle to the breast unless you are comfortable switching to formula before too long or you are happy to spend a lot of time pumping.
We managed like that with mostly breastfeeding and just occasional bottle feeds until he was 7 months old, when I went back to work. At that point I began expressing milk twice a day for him to have bottles at the childminder's, and continuing to breastfeed in the mornings, evenings and at weekends. He is now just over 10 months old and we are down to three feeds a day, one of which is pumped breastmilk.
One more thing: I would try to avoid replacing middle of the night feeds with your partner giving a bottle until your baby is a bit older, unless you are really really struggling with the lack of sleep. Breastfeeding at night is important for keeping your supply up, and I think it also helps the baby to settle down to sleep again much more quickly compared to a bottle feed.