I do lots of testing of apps in real phones, not emulators.
The thing is that the phones must be connected to the PC all day. Because of this, phones battery get swollen and I have to buy phones regularly.
Do you know any android phone which can be connected and on all day all week without getting swollen after a time?
Must be real phones, emulators are descarted.
The best way to prevent swelling is stop charging at 80% or less (some phones have this feature, or you can use homeassistant with a smart plug), and keep the phone cool below 21C/70F.