Creating a GeometryCollection from a Nanite Mesh is taking too long.

I tried creating a Geometry Collection in Fracture Mode to apply destruction effects to an environmental prop mesh (like a giant rock) obtained from the Megascan Library.

This worked fine, but the creation process took a very long time (the editor was freezing for over 10 minutes before it finally finished).

The mesh in question had a very large number of polygons, so I thought that might be why.

So is it not recommended to apply Facture to a mesh like this?
Or is there a proper workflow for applying destruction to these large meshes?
Any help would be greatly appreciated.