Need help with partially transparent mesh

Hello there,

As you can see in the file attached, one of my object is transparent, as if the normals were reversed or something like that. The thing is that the normals aren’t reversed (according to Blender).

8996737--1239190--SeeThrough.gif

I’m a beginner and I can’t seem to find a solution to this problem.
If anyone could help me have a better understanding of the situation that would be really nice!

Are you sure? Look again after this:

8669961--1167858--backface_culling.png

8997484--1239370--upload_2023-5-7_16-25-10.jpg
It seems ok with backface culling, same with Face Orientation enabled
8997484--1239376--upload_2023-5-7_16-27-21.png