Decline in milk that’s pumped

My little one is almost 4 months. She breastfeeds for almost every meal, except for dinner. Dad gives her one bottle a day which she takes no problem. When she was 2 months old, I pumped like crazy and could produce 1-3 oz in one sitting no problem. Around 3 months old, I started to notice it becoming more and more difficult to get the milk out when pumping, as if my boobs became immune to using the pump. I know the milk is in there & I know my little one is getting enough, but why isn’t it coming out? pump sessions now only result in 1/4-1oz tops!

Has anyone had similar issues where it’s become more difficult to pump the milk out around month 3-4? Does anyone have any tips or pointers?

So far I’ve tried:

-hand expressing

-drinking tons of water

-eating tons of oats

-dark beer

-lactation cookies

-mother’s milk tea

-pink stork tea

-fenugreek capsules

-pumping right after all her feeds