I don’t understand my supply

Hi everyone! Looking for some advice on understanding what my supply is doing lol. I had my twin girls in January at 30+2 and they were in the NICU for 7 weeks. During their NICU stay I was pumping every 2.5/3 hours and was getting roughly 240mls each pumping session. Which was more than enough and built up a freezer stash. When they came home it was super hard to pump so I started BF them in between bottle feeding. All of a sudden when I would pump (like 4 times a day when I was bottle feeding) I would get like 350mls. Then overnight my supply dropped to like 50-100mls per pump. I stopped BF and started EP again and my supply went back up and it increased a little/went back to getting between 180-240mls per pump again. But now they have like 120-130mls every bottle feed so I’m not making enough and having to dip into my stash/supplement with NP2 formula. I’ve gone back to a mixture of bf and bottle feeding with expressed milk now - but I feel like the girls aren’t satisfied when I bf them. At the moment I am bottle feeding them their “big meals” every four hours (and pumping during these feeds) and bf them their “snacks” in between these feeds when they ask. Now my supply seems all over the place. My first pump of the day I’ll get 300mls then throughout I’ll get anything between 140mls and 50mls. I’m so confused, help.

I am also eating the oat cookies/drinking lactation tea etc.