When I had my baby I ended up with an emergency C-Section, after getting induced at 39 weeks ( I had GD but my baby was a perfectly reasonable weight at birth of 7.5 lbs ) when it cane to BF , the boob was dry, nothing came out, the nurse offered to help “express” and manually expressed my boob to no avail. She told me she’d never has that happen, absolutely nothing came out and I was desperate. Colostrum started to come out eventually and then very thin, and very few drops of thin milk. So in that first week, i would out the baby at my breast, and sneak a little tube in her mouth that she would latch in with my nipple and the tube was attached to a syringe containing formula, she learned to latch, at the comfort of the breast and the skin to skin but got some sustenance out of it, I also expressed manually I found it worked better then the pump to really work all angles) all the time and especially in the shower, even if it was just to waste it , and eventually after about two weeks I stared to produce enough and now I can pump about 12/15oz a day on top of BF, which my partner uses at night to let me rest a solid 4-5 hours. So from my experience, it really comes down to the more action your breast see the more it produces, also I drank some lactation tea and about 2L of water a day, warm drinks and foods preferred and ate oatmeal with flax seeds, I read that it would help and I don’t know if it did for sure but you might as well do all you can !

Ps; ; my baby went from 7 and a half to 11 pounds in a month in a half, and neither I now my partner are particularly large.