https://www.gsmarena.com/lg_k7-7848.php
Your LG K7 is a six-year old phone so it's not surprising that some odd, random problems start occurring. Just off-hand it sounds like the installed Android operating system on your phone has been corrupted in some way so it just can't boot up and run normally now. This requires you do flash an appropriate, matching firmware -- flashing the ROM replaces the existing Android OS with a new, clean Android OS (Essentially similar to using a Restore disc/media to replace the installed OS with a clean one in a desktop computer). Note that your phone's internal storage media is divided up into several partitions, with most of them dedicated solely to the operating system, and one being set aside as the general user storage partition. A Factory Reset only wipes that user data partition clean (that's where all your personal data is stored), while flashing the ROM replaces the existing operating system. Two different tasks that do two different functions.
But getting back to your phone problem, you can continue trying to 'fix' your phone by trying to flash the ROM but don't forget this is a six year old phone so you should take into consideration how much time and effort you want to put into restoring this phone yourself or paying a local service shop to do the same, or instead just start looking into buying a new replacement phone.
Also, hopefully you backed up your data before your did that first Factory Reset, yes?