This^^
Yes, keep your bottle schedule as is! Give baby the rice packs either before or after the bottle, whichever works best for you and baby.
Don't drop any milk even with feeding them. My daughter is older she's 7 months but her schedule usually looks a bit like this. 5am bottle 9am bottle 10 am breakfast 2pm bottle 4pm dinner 5:30-6pm last bottle and bedtime x She occasionally has something at around 12 usually an extra smaller bottle or a small lunch but 9/10 she's napping so doesn't x
Be aware that starting solids is really tough on their tummy and guts, especially before 6m! Research shows risk when starting solids before 6m, baby rice is a very old concept, not very modern to use, highly processed and not very healthy It is nonsense to start solids for bowel movement!!! With 4 m the muscles are not strong enough and they cannot move enough to get guts working properly (one of the reasons why they should be able to sit)
Before 12 months, the primary source of nutrition is still breast milk or formula. About 30 minutes to 1 hour before giving solids, give a bottle so that they get their nutrition of that and the solids is to get used to. Solids should not replace a bottle prior to 12 months.