Breast milk quality, quantity and effectiveness??

Hi ladies. I have a 10.5 week old son who is very big for his age. For various reasons breastfeeding didn’t work out in the beginning, So he’s been on formula almost entirely.

When my milk did come in I started pumping and have been supplementing whatever I pump to him daily. I only ever get a few ozs per day though and lately I’m lucky if I get 1 oz total for the day. I have tried a lot to increase my supply without much success.

Now I’m back at work and have even less time to pump and am getting very little milk that’s also very very “thin/watery”.

So here are my questions -

how much pumped breast milk does it take to really benefit the baby - Is 1 oz a day really helping him that much or even at all?

Since he’s not breastfeeding my milk isn’t necessarily tuned in to his specific needs needs is it? So it won’t really help him fight a cold or some other virus.

I’m just not sure I want to continue pumping since it takes up so much time and seems like the little milk I’m getting probably isn’t even helping him that much, but I don’t want to stop if it his helping him.

What do you think?