Sony WH-1000XM4 Bluetooth not working

I've had these headphones for a few years, and just recently, the battery ran out (I think), the headphones turned off without giving me the battery low warning. I plugged them in for a bit, and when I turned them on later they wouldn't connect to my phone. I've tried everything, I turned off and on Bluetooth on my phone, on and off my headphones, and then I thought I should re- pair my headphones to my phone. After unpairing, I realized that my headphones won't go into pairing mode, no matter how long I held down the power button. I looked online, but there is very little on this specific issue. I tried factory resetting them, by holding both the power and custom buttons simultaneously but nothing happened, both plugged in and unplugged. I'd try using an aux cord but I don't have one ATM. Still can't get my headphones to go into pairing mode, like I have a million times before.