I do Wigle wardriving with a dedicated cheap phone these days. (Moto G Stylus 2023)

In order to prevent issues this time around I've preemptively removed the back of the phone, and the camera modules so I can have a nice flat phone. Then I bought a heatsink nearly the same size as the phone itself. I've got thermal pads on the SoC which sits lower than the battery and the heatsink itself had thermal adhesive on it pre-applied which is sticking to the battery/phone frame holding it to the phone. No more phone overheating worries and if the battery goes pillowy it should just pop the heatsink up instead of warping the whole phone.