Best bottles for breastfed babies?

I am trying to get my son who is exclusively Breastfed to take the bottle for over a month now, he is almost 8 months and I have to return to work. Well I’ve had no luck. I’ve tried so many different bottles, tried having two other people offer it to him on different occasions. He will just cry and cry until he falls asleep. I’ve tried cups with a straw, sippy cups, training cups. I’ve also tried doing formula and breast milk. I am at a loss. What do I do???
Thank you in advance