Auto Smooth, Recalculate Normals and Symmetrize did not work for me. In case these also did not work for others, here is the solution that worked for me:

Select mesh > Go to Edit Mode > Select all faces > Go to Mesh properties tab (at top of 3D viewport in Blender 3.0) > Normals > Set from Faces.

Note: After this operation your mesh may look flat shaded. It is most likely not flat shaded. Therefore, don't waste your time trying the Smooth Faces operation. Instead in Edit Mode with all faces selected, you may notice they have all been switched to Sharp Edges. To fix this use: Ctrl E (will bring up menu) > Clear Sharp.

Hope this helps.

Auto Smooth, Recalculate Normals and Symmetrize did not work for me. In case these also did not work for others, here is the solution that worked for me:

Select mesh, go to Edit Mode, select all faces, go to Mesh menu at top of 3D viewport in Blender 3.0, Normals > Set from Faces.

Note: After this operation your mesh may look flat shaded. It is most likely not flat shaded. Therefore, don't waste your time trying the Smooth Faces operation. Instead in Edit Mode with all faces selected, you may notice they have all been switched to Sharp sdges. To fix this use: Ctrl + E Edge Menu > Clear Sharp.