I have the console filled and so didn't have room for one of those inserts folks have made. Been keeping my glasses in the cup holder up until now. This is a case that snaps behind the touch screen. Out of sight to driver and passengers so it keeps the dash looking clean. I considered having it hang below but then it would have interfered with the opening of the charging area. It is a little awkward to reach behind to grab the glasses but it works for me so thought I'd share in case anyone else has a similar need.
Glasses Case for Tesla Model 3 by TickTock
Glasses Case for Tesla Model 3 by TickTock