ADB phone access via Windows 10

[gyw]

Unfortunately I broke the screen of my beloved 6P today and have spent the last 8 hours trying to figure out how to recover everything from it. It's still working as I can hear notifications and phone calls but the screen is blank.

After searching everywhere (xda, stackoverflow etc.), I'm a bit stuck and was wondering if anyone can help. Here's my plan:

1) I want to emulate the phone screen on my PC via USB using Android Control
2) I need USB debugging mode to access the phone via ADB
3) I need the correct (Google) USB drivers installed on my PC to access ADB

I have downloaded several tools/drivers and this is how far I got:

1) Windows sees/recognizes the phone under Devices and in Device Manager (as It does normally) - I am unable to access the phone because it's not in file transfer mode
2) When I run adb devices, the list is empty
3) I tried to update the driver to the latest Google USB driver but Windows 10 won't let me (windows has determined the best drivers etc. etc.)

I can't be sure what is blocking access via ADB. I'm sure I enabled USB debugging when I first got the phone but it was a long time ago. I read that I might need to disable Windows Driver Signing to install the latest Google driver but I haven't tried it yet.

My question is, how can I tell if it's USB debugging or the Driver? Any help would be greatly appreciated!

 

[GSDer]

2) When I run adb devices, the list is empty

This tells me that you don't have USB Debugging turned on. Sorry, game over.
If you have something on the phone that is not backed up by Google (all SMS/MMS [Google only backs up the last 30 days of SMS], media files, other?) then you should get a cheap replacement screen and recover whatever is necessary.
Since Google Photos takes care of pictures/videos, and Google has your Contacts, Calendar and Gmail taken care of I'm not sure what you think you're going to be missing but you know best.