@chidu, my AR scene has 21,000 tris. The bin.xz file is about 1MB. I have found through trial-and-error that I must keep the scene data simple. This includes meshes, textures, and shaders. I have a few textures files, none are larger than 1024×1024. I also try to keep my shaders simple. My goal is to limit the load on the GPU. The Snapdragon 855 on the Tab S5 does not seem to have any problem with AR scenes of this size.
If you are trying to get building-scale AR to work, you are attempting something that I have not. All of my AR work has been human-scale or smaller. I wonder how well the Google and Apple AR sub-systems are at anchorless AR environment mapping at such a large scale? Have you tried to get a very simple scene to function at building-scale? If it were my project, I would try something simple like sticking a few default cubes to the font of a large building and testing if Google AR Services can manage the markerless tracking at that scale and distance.
Good luck.
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