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.
Your sample size is 1. Sure, you can get a phone that won’t have battery swelling after 5-10 years. My old Samsung S9+ doesn’t have any swelling yet, and I’ve had it since around when it came out in 2018. Whether or not swelling happens to any given phone is more or less down to luck. You might want to avoid Samsung phones to be safe though because there was that whole battery swelling issue with almost every phone from the S20 downwards a few years ago. Other than that I don’t think there’s much of a difference*
*Probably something to look for reports/statistics on though