This worked for me. MSFS loads the graphics in at Medium despite what you have set in options. You need to set to medium, save then set to High-End or Ultra etc and it will keep those settings for the session. Once you come out and start again the graphics are back to medium.What the Video and try it yourself.
It’s pretty sad when developing a reliable UI menu is a major challenge! 
Ths topic on graphics not being saved has been around for a while.
See this post and other linked threads
Still waiting on seeing this work anywhere other than EGNX. Seems like an airport bug + placebo effect
Sim Update 5 is by far the buggiest updates of them all…based on how much the community is finding, it feels like we’re back to square one with months of waiting ahead for Asobo to fix them all… I wonder how porting this game to Xbox caused so many things to break.
I doubt that’s the only cause. Still, there’s a hell of a lot to do. To begin with the needed to port the entire graphics engine to use DirectX 12! And support DX11 simultaneously on PC. Then there’s the input method: the entire sim needs to work fine with just an Xbox controller, including selecting every single button or dial in every airplane, and even using touchscreens (actually, does the G3X Touch work on Xbox? I assume it does).
Those are pretty big by themselves. Then we have the whole optimization deal, which also probably touches many parts of the graphics engine (including shaders – the lack of volumetric lightning was a shader bug, so they probably rewrote that shader), all models and all textures.
There’s already a topic regarding this bug: