I am not a fan of split units being used in bedrooms unless there's a strong need for AC in the summer. The reason? You've got a unit that runs with a fan and quite often the fan gets to the point where the air circulation feels cold (it isn't it's just the sensation of breeze).
As Timmay has alluded to over all of these years it's a process to figure out what works best. I would probably start with getting an outdoor unit that can have multi units added to, but start with one or two units in main areas only. I was very surprised how well our single 7kWh unit was able to push heat throughout the house.
My question was about bedroom cooling, we already have a heat pump for the living areas.