To my surprise I couldn't find options to install a storage water heater that can centrally provide heated water to all bathroom

I went to HomePro, Harvey Norman all selling those instant water heater.

I don't want to use those cos need to hack bathroom, pull wiring, ugly and comes with electrical hazard. I want to use back original shower head

Those tank one I see a lot of benefit however I have lots of questions

1. Can my existing PPR pipe allow the installation?
2. Do I install one in each bathroom above the ceiling or can install one at the incoming main?
3. Where to shop for this?

In Singapore this seems to be common. Got option to go with slim design to hide it