next pinephone model, maybe "pinephone handheld".

[diederik]

the biggest drawback in PP/PPP is battery life. Easy fix would be to increase battery size.

I think the better fix would be a smaller production process.
The Quartz64 devices use a 22 nm process and that already runs MUCH cooler then the Rock64.
I don't know at what process the PPP is made, but likely (much?) higher.
For comparison: a Samsung Galaxy S7 (2016) is made on a 14nm process and recent (high-end) phones are made on (less then) half of that.

Smaller production processes mean higher energy efficiency and lower temperatures, which in turn means the CPUs don't have to get throttled as much.