Earlier quoted context omitted.
Yeah battery will virtually always be the first to go. Unless you crack the screen.
in my experience, it's the charge port that goes. My last two devices, each of which I had for 3 years, the charge port failed before the battery did. I just finished fixing my current one. Although I did decide to do a battery replacement anyways while I had the device open. But that was just because of how hard it is to open them at all. My battery health monitoring app said it was at ~80% health still. And while t…
I have had this problem on a regular basis with all of the iPhones I have owned, and the problem has never been that the charge port is dead, but that dust and/or lint has gathered in it.
The solution is very simple: use a tootbrush or similar, preferably something plastic that won't break, BUT NOT ANYTHING METALLIC, to dig out the dirty stuff. Problem solved.