blender shading issues

[steam tractor man]

this shading issue was made by the way by duplication, mirroring along the x axis then moving along the x axis , snapping the mirrored to the opposite side then selecting all and merging by distance.
how do i fix this issue? uvs? I can attach the .blend if needed.Chode FM

 

[Miner34]

Try recalculating normals (while in edit mode, press f3 and search for "recalculate normals", then press enter).