just quickly

cow's milk is not ok at his age

i have come across plenty of bf-ing mums that do the drop off CC feed (give yourself 30mins before you HAVE to leave), and the pickup feed (at childcare), and their child is very happy to have that - reconnecting with mum (plus they love the bm).

Going from bf-ing on demand, to being away from your child part of the day/week whatever, is going to take adjustment, and the trialling of a FEW different ways of doing things.

you try something out
observe how he reacts
then make your decision, do i keep going with this?
or try something else
it'll take a bit of trial n error, to come up with what suits you and your bub.
e.g finding out how he WILL accept EBM. (syringe? sippy cup? spoon).

don't forget breastpads for you at work (and even an extra top in your bag, to change if you need to.)

breasts are amazing, they will adapt to the changed feeding schedule.

hope your workplace is good about expressing AT work. (to give you relief).

"until one, food is for fun".