My wife and I have been longing to hangout with just the two of us but our exclusively 4-m.o. breastfed baby can't be left home with just her granny. Any tips on how can we have a good date?

Yes, my girl hated bottles too, but she amazingly took to MAM. Do try out more bottles and teats before calling it a lost cause. You can also try feeding her via syringe. It takes a long time though.