I finally found roof shades that for M3 2021!

[Yeslak]

Collapsible sunshade will be very helpful in the summer, and It is easy to store when you don't need them in the winter.

Cooling Glass Roof Sunshades for Tesla Model 3&Y

The cooling sunshades are custom designed for Tesla Model 3 and Model Y glass roofs and made of cooling fabric with silver pressed reflection to furtherly to reduce the heat into the cabin during hot weather and make your ride cooler. It is also able to block out light while taking a break or...

www.yeslak.com

We have the sunshades for 2017–2020 and 2021+ Model 3 available in our US warehouse.
It is single layer made of cooling fabric and a reflective coat for the roof.

 

[Zacster]

Here it is August 24, 2023, and I haven't put my shades up. Maybe they helped, but the car itself is comfortable without them. Just turn on the AC remotely if the car is parked in the sun. I didn't put them up last year either.

 

[blackT3$!@]

Here it is August 24, 2023, and I haven't put my shades up. Maybe they helped, but the car itself is comfortable without them. Just turn on the AC remotely if the car is parked in the sun. I didn't put them up last year either.

My Tesla can get up to 160 degrees inside in the direct sun. We just activate climate control on "LO" 10 mins before we depart and the cabin is nice and cool for the trip.

 

[melvladimir]

the car itself is comfortable without them

At noon I feel the sun on my head and this is not comfortable at all. We don't have such extremely hot weather, but 30-36*C (86-95*F) is very hot for me.

And this is not about keeping a parked car cooler - I can switch on pre-cooling or "keep cooling" and it makes the interior comfortable, this is about driving in the direct sun. BTW, the option "keep AC on" also takes less energy with these shields.