You have a lot of materials in your current object, it will be much more convenient to use the Selected to Active bake mode:
- Duplicate your object
- Unwrap the copy with the Smart UV Project mode
- Remove all the materials of the copy
- Give it a new material with an Image Texture, in the Image Texture create a new image texture that you'll call Bake for example
- Select the original object, shift select the copy
- In the Bake panel, choose Bake Type > Diffuse, disable Constributions > Direct and Indirect, enable Selected to Active, give a bit of Extrusion (0.1)
- Bake, check the result