iPhone 7 won't turn on after hard reset

Hello, I was wondering if anyone had the same issues as me regarding the iPhone 7 and/or might there be a proper term for it / solution?

So, I left my phone to charge overnight and when I woke up, I tried turning it on but it was unresponsive. I tested the plug in the wall and the charging cable with another phone and it charged that separate phone just fine. So, I deduced the problem to be something with the phone itself, unrelated to the plug and charger. I looked around on the Internet and tried that "Power button + Volume Down" reset several times- up to a minute of holding down- and still nothing. I also tried holding down those same buttons and plugging in my charger at the end of the interval. I did clean out my charging port with a plastic toothpick, until no clumps of lint could be found, and retried that reset after letting my phone charge for 30 minutes but I still had nothing. I've never dropped and cracked the screen on this phone and have owned it since August '17 though I've never had something like this happen. I do share the Life360 app with someone and they said that my phone was reportedly at 68%. I have also tried connecting it to my computer and putting it in DFU mode but it wasn't detecting the phone.

Are there any other possible solutions I should try and is there a proper name for this kind of error?