Expressed or supplemental bottle experiences

My baby had a slow weight gain so we are asked to supplement with formula after every feed. The only pro for that is anybody can feed the baby and mum can take a break. Now my LO is 8 weeks old and we dont supplement anymore like that.. i do give her a bottle once a day with either expressed milk or formula when but thats also top up and not a full feed. I give her bottle so she stays used to it and doesnt reject it later on

I expressed milk since day 3 (struggled to latch), and I still express now once a day (7 weeks).
He had mostly expressed milk up to week 3, a mix up to week 6 and we are now exclusively breastfed.

When I was supplementing with a bottle (so between 3 and 6 week), I used to give one in the morning (10am) and one before bedtime (10pm ish).

Especially on hot days, it gave me a little peace of mind that he was getting at least 2 big feeds in a day! I also felt like a bottle before bedtime help to have a little longer first stretch of sleep 😊

I had to pump due to jaundice. Basically I was told to top up with formula. So whenever he had formula, I would pump to simulate the feed (this is really important). I decided to give the expressed milk during the night feeds so that I was sure of how much he had because he would be sleepy and fall asleep on the breast and he was impossible to rouse to drink more. Eventually I was pumping enough that I didny need formula and then suddenly I started having an excess I could put in the freezer. It was at that stage, around 3 months old, I dropped the pumping and have just ebf since. Now im back at work, I pump at work and take it home for the next day whilst im at work