How do i fix the way Blender exports models?

When i export a model with Blender (a gmod playermodel to be specific), there seems to be black edges on the model when i’m in game, like some sort of lightwarp issue that can’t be fixed by editing the textures. In another model, the pants get some black crevices of some sort.
As far as i know, exporting with Blender seems to be the issue with these black stuff coming from my models, is there a way i can fix how Blender exports models so i don’t get these black stuff on my models in game?

did you recalculate the normals?

When i do the command nothing happens, how do i properly do it?

I figured out how to calculate normals, but unfortunately, that did not solve the problem.
I still need a solution.