What Blender parameters you guys are using for basic window’s building when you want it glass but not transparent because there’s nothing (yet) inside? I set these and not happy with the result:
(Surface) Metallic: 0.9
(Surface) Roughness 0.3
(Material Mode) MSFS Glass
(Material Mode) Alpha multiplier: 0.23
Thanks for your help from a beginner in Blender 
Try lowering the roughness to something below 0.05,
Glass are smooth 
(they changed how glass behave in su6, before that your glass value were still fine)
The less roughness, the more reflections you get
Also if haven’t anything inside i would go with alpha above 0.6
You can However in the meantime throw there some basic items like tables and chairs