It seems the same steps are valid for Max version as well. Someone even used 1050 for a benchmark here https://thegamecreators.com/post/gameguru-max-performance-improvements
After some thinking, the single level approach is definitely the culprit. This is probably the first time I've seen someone do this as every other game was split into progressive story levels.
I also tried lowering shader settings as follows:
visuals.shaderlevels.terrain=2
visuals.shaderlevels.entities=2
visuals.shaderlevels.vegetation=2
visuals.VegQuantity=60
visuals.VegWidth=35
visuals.VegHeight=35
visuals.CameraFAR=200000
visuals.TerrainLOD1#=3000
visuals.TerrainLOD2#=4000
visuals.TerrainLOD3#=5000
visuals.DistanceTransitionStart#=2500
visuals.DistanceTransitionRange#=300
visuals.BloomEnabled=0
visuals.DepthOfFieldIntensity#=0
visuals.MotionIntensity#=0.3
visuals.FXAAEnabled=1
visuals.WaterWaveIntensity=80
visuals.WaterReflection=0.2
visuals.WaterSparkleCol=1.0
visuals.SkyCloudScale=40000
visuals.SkyCloudThickness=50000
visuals.SkyCloudCoverage=0.9
visuals.ShadowSpotCascadeResolution=256
visuals.SAOIntensity=0.3
No result whatsoever, which means the single level is so huge it doesn't fit into 4GB of video memory. 3060 has 12 GB of VRAM which allows it digest less optimized games better.
I'm just saying, I was able to run games like Cyberpunk, Witcher 3, RDR2 and so on. Those were able to run because modern engines use streaming assets plus splitting into levels to make the maps fit into that 2-4GB VRAM bill. As Game Guru MAX can't do that, your biggest task would be to split everything into levels.
You can join in Blender or attach in 3DS max the cars that use the same material and texture together, the same goes for decorative elements, walls, windows, doors if they are separate to create chunks of similar meshes that will be loading and unloading by distance. In other words, each level should contain only meshes that are used by it. It will reduce your drawcall count as each separate piece of mesh takes another drawcall to be rendered.
Optimizing your projects will save you tons of issues and attract wider audience as not everybody can afford better PC these days. That also will improve your skills as a game developer. Thanks for listening, I appreciate you taking time to fix everyting.