old school trick is use a length of black electrical tape along the upper part of your visor to create some sun block. I've been doing this for years. It's not a 100% but it helps when you have those moments of sun flicker on the country roads.
Yep, depending on how high the sun is - I regularly use blue painter's tape up there when heading home after a sunrise.
Keep a roll in each scooter.
The morning in question - left too soon, and had the sun under the stop lights, and practically on the pavement for too much of my route.
So, I parked.
I have a problem with fly-screen glare on my Paiggio - so on the very dark morning rides I'll put 2" of tape near the bottom edge of my visor so that I can see better into the dark when looking ahead. Works a treat.
Stig