Shading issues after normals baking a). I baked normal map and applyed it to lowpoly mesh and I made 3 clones of it with different options for demonstration purposes
b). I got the issue with shading
What I want to be: lowpoly mesh without additional geometry and with correct shading and smooth
At the screenshot you can see (from right to left):
1.highpoly mesh that I baked from
2.smoothed lowpoly mesh with additional geometry I want to reduce, but it has correct shading and smoothing
3, 4 and the second screenshot. lowpoly meshes that I want to produce, but with correct shading and smoothing
So how can I do this?


blend_file
To fix to shading in Blender, select the 2nd object in Object mode ...

go to Object Data Properties tab

expand ► Normals, and activate ☑ Auto Smooth, 30°
expand ► Geometry Data, and clear the x Custom Split Normals Data


go to Modifiers tab

remove the WeightedNormals modifier