For example, I have added a fan to home Assistant, that has fan speed, on and off, etc. in different entities. When I create a Helper I can only add one of them, so I can’t use the normal home Assistant actions to control the fan.
I hope the problem is understandable. Sorry for mistakes, English is not my nativ language.
There are only a few that can accept multiple entities… so my guess would be that the reason you can’t add the described entities is that they are all different entity types i.e. sensor, binary_sensor, number etc.