Moto G3 (6.0) - Can't access files, tried many guides

I'm unable to access files on an Moto G3 updated for Marshmallow 6.0 ("this folder is empty" when connected to a pc, tried on several computers). I tried several fixes and guides but nothing out there seems to work. 1. https://productforums.google.com/forum/#!topic/nexus/6pbWH1yvPMs Swiped down after connecting to pc, there are no notifications nor options to choose from. 2. https://android.stackexchange.com/questions/134230/sd-card-not-showing-files-when-connected-to-pc Been there, did that. Rebooted, waited... once again, no files & no notification to change USB connection mode. I did the wipe cache partition part too and waited for some good 10 minutes after doing it before connecting USB 3. I wanted to try more options via USB debugging & such, but I cannot enable that either. I tap a bunch of times on top of the "build number" option in the menu and nothing at all happens: http://wccftech.com/enable-developer-options-in-android-6-marshmallow/ 4. I went on to search how to root the device which seems to require USB debug mode which I could not enable on 3. I'm not sure if I'm missing something obvious here but none of the answers/guides I tried so far seem to work. Anyone knows what's going on?