Baby hates formula?

Ma

My baby is almost 4 months old and is breastfed, she also occasionally has breastmilk from a bottle and we have no issues with that. I'm going back to work in 2 weeks and I struggle to make enough milk when I pump. I've tried hand expressing, manual and a double electric pump, smelling stuff of hers, looking at photos, videos of her crying or giggling even holding her. My boobs hate pumping and it takes me 3-4 pumping sessions to make one bottle😣

We've decided to give her formula while I'm at work so yesterday we tried to give her a bottle of formula for the first time to make sure she takes it.

My husband tried to give it to her and she wouldn't even latch onto to bottle and when he moved the bottle she spat the formula out. She started crying and fussing but still refused the bottle, eventually we gave up and I put her on the boob. When she finished I immediately put the bottle in her mouth and she had around 15-20mls of the formula but still spat out the last mouthful she had (I think because she realised it wasn't breastmilk).

How do I get her to happily take it? Are there any tips or tricks to get her used to it?