Sketchup 2020 - Shadows

FWIW, I did let CleanUp3 run. Here is what it did.
Screenshot - 11_5_2020 , 6_56_47 AM

And another purge…
Screenshot - 11_5_2020 , 7_03_12 AM

Even with that I’ve only reduced the file size by about 15%. There are a lot of obese components in your model that could stand to go on diets. If they did and slimmed down, your model would be much easier to work with.