Moto G4 black screen - what exactly is the problem and how can I fix it?

Hey r/AndroidQuestions, having an issue with my Moto G4 (not sure of the exact model) and I'm wondering if you could help me figure out exactly what's wrong with it and what I can do to fix it

• 90% sure the issue is water damage, although it has been dropped a few times (usually inside a protective case)
• At first it stopped being able to make or receive calls and gave me the "Service network unavailable" message, but since it did work in certain places I'm not sure if the issue is with the phone or just the signal in my area
• Recently the phone stopped turning on properly, sometimes it wouldn't work at all and sometimes I couldn't turn off the phone when it was already on, making me think the issue was with the power button
• Now the phone won't work at all, just gives me a black screen. When unplugged none of the buttons do anything, although I think it did make the charging light flash a while ago but it's stopped doing that now
• When plugged in, the charging light flashes three times and then stops. Trying to switch it on makes the phone vibrate, but I still only get a black screen. I've tried pretty much every button combination, nothing, even Safe Mode wouldn't come up.
• While it's plugged in the PC will make the "device plugged in" and "device unplugged" noises in a loop. Occasionally the computer will detect the phone completely, but it shows nothing on the file explorer, not even the SD card in the phone, and won't let me import pictures or videos (this might just be the computer being temperamental though). Either way it never connects for long and ends up disappearing from my PC after a few seconds
• Sometimes when I plug it in the light will flash continuously, and turning it on will lead to it vibrating something like every ten seconds and going on like this indefinitely. I haven't seen it do this for a while however
• Put it in a bag of rice, nothing
• Just tried it again, the light blinks four times while the phone's plugged in, but now none of the buttons does anything. Held down the safe mode combination for a while, LED started blinking twice, waiting a few seconds then blinking twice again, and vibrated when I let the buttons go

That's everything I can think of for now. I don't mind having to fix it myself, but either way I could really do with getting it working again as soon as I can. If anyone could give me a hand with this, it would be really appreciated.