Unable to Hard Reset L70 D320n

I have an LG L70 D320n which I had as a backup phone a few years ago. I need to send my current phone off for a warranty repair, and want to use my LG phone again, but I can’t get it to work.

I tried to follow steps similar to https://www.devicesfaq.com/en/reset/lg-l... but am unable to fix my phone. When I turn it on, it just hangs on the LG logo. I have tried pressing Volume Down + Power to do a hard reset, and it just hangs on “Factory Reset Processing” page (the arrows don’t even turn). I have also tried to put it into Download mode by holding Volume Up while plugging in a USB cable, but nothing is working.

I have a feeling I may have rooted it in the past, but surely there must be a way to get past this issue so I can reinstall the factory ROM (which I have on my computer) …

Please, someone help so I can send my phone off for repairs. I need a phone to use in the meantime, and this is the best backup I have access to.