Japan has the solution to this. Tubs are connected to a smart system and you can start your bath from, say, the living room via a panel. You can specify what time you want it filled up at and at what temp and it does the rest.
Some tubs even support re-heating the existing water, so you can re-use the same bathwater the next day or later in the evening for other family members. (in Japan it's assumed you're going to shower and clean your body throughly before entering the bath, like in a hot spring/public pool, so the water doesn't get so gross)