I gave it to a technician with all the info, we'll see what they figure out. If they do, I'm gonna comment the solution(if there is one) for someone who may have this problem in the future. Thank you so much for your support.

I had backup, but my whatsapp didn't backup for some reason, so I lost that unfortunately. Nope, no signs of life at all. I've been charging it for the whole day with different cables, bricks, and outlets. I'm gonna leave it overnight just to be sure. Yeah, I plugged it into a sonoma mac and a pc with itunes, nothing showed on both. Also I'm not really sure if I'm entering DFU correctly because most tutorials assume turning off a working phone and I don't have that, so there's also that.