Ok regarding the ride comfort - But you were warned...haha. Seriously you might be ok but there is zero chance I would as I reckon the model 3 with standard 18" at 36 psi is bearable. Not sure if the Merc E had air suspension but the Y certainly doesn't.
In regard to the glass. I am in Sydney, have a model 3 2022 and use the front sunshade since summer commenced down here.
It is a dual model with the cloth and a 'metalized' coated 2nd insert.
After installing I could still feel a little heat, so I added a 'metalized bubble wrap' that I have previously used for some roof insulation.
This made the heat coming through bearable under all circumstances now.
On the opposite end in winter the glass roof adds to the cabin comfort and is a definite plus.
I think with the Y the use of a sunshade is a little more of a hassle as the glass roof doesn't have the cross member like the 3 so you either have full coverage or none at all.
You could always get one of these for the model Y - just pay someone to install it. Not too sure how much heat it would stop but at least no direct sun.
otrifowd.com
Note in USD.