Baby drink milk only when she sleeps.

Mummies anyone experiencing LO only wanna drink milk when she sleep? And not always successful. In the end we started solid earlier, but all the more she dont want to drink alamak Milk intake drop from 800-400ml! That is almost half… and the gap between milk is 6hours,10-12 hours kind. Such a stressful journey But she eats solid super well! LO is now 5.5 months I even bought the bottle feeding aversion from rowena bennett. The solution is to stop solid temporary. I am abit scared to follow this method in case baby in the end become dehydrated. Please help!!