Things are never that modular.
To prevent clipping entierly, you need to remove geometry however you see fit.
you can’t expect the maker of a t-shirt asset to modify the mesh you made your self to remove the correct amount of mesh from under the shirt.
Likewise, you can’t expect the shirt maker to be limited in sleeve length by a standard without majorly compromising any and all originality.
Thats why what you want is something you must learn and actively DO rather than a script you can run.
Just buy an asset that’s rigged to the epic skeleton, delete the part of the mesh from under it that is not needed. And export out as a new skeletal mesh - a dressed asset.
(You’ll also have to correct the UVs. Possibly unify the material into one if you need mobile compatibility, and maybe set up a lightmass compatible no-overlap UV.)
Now, the assets can have bad weight paint, so in that case the maker of the t-shirt would be the one responsible for bad work.
same for bad vector paint/cloth paint.
Again. If you want to keep the existing stuff, you need to keep the vertex order untouched.
so you delete under the character skin, export it out separate as “skin for t-shirt x” and you add the shirt on top with master pose component.
either approach is maybe 10m of work. If even. Save for when you have to mess with UVs i guess.