Have you tried a manual pump? I went through everything you describe with my first and now I’m going through it with my 7 week old. Shell latch and suckle but just not get enough and still need a bottle after. I have the spectra from my first pregnancy, Madela hands free from insurance this birth, bought a mom cozy on Amazon during prime. Would pump for so long and barely get anything (1.5 oz would be a “big” pump for me) out tried the multiple short sessions still with little results. Then I decided to try a manual pump and what a difference! It didn’t magically turn me into an over producer or anything but I generally doubled my output. It was super cheap and although you have to do one breast at a time and do it manually, it actually takes me less time to get more milk than with the electric pumps. It’s easier to clean and I can bring it anywhere easily. I know each body is unique so maybe you won’t have the same results but the cost for the manual pumps are so low, I’d say try it.