import bpy

def do_copy_pure_geometry():
    context = bpy.context
    src_ob = context.object

    if src_ob.type != 'MESH':
        return

    if context.mode == 'EDIT':
        bpy.ops.object.mode_set(mode='OBJECT')

    src_mesh = src_ob.data
    dst_mesh = bpy.data.meshes.new(name=src_mesh.name)

    def copy_over(attr_name, sub_name, components=1):
        src_attr = getattr(src_mesh, attr_name)
        dst_attr = getattr(dst_mesh, attr_name)

        if len(dst_attr) != len(src_attr):
            dst_attr.add(len(src_attr))

        arr = [None] * (len(dst_attr) * components)
        src_attr.foreach_get(sub_name, arr)
        dst_attr.foreach_set(sub_name, arr)

    copy_over("vertices", "co", components=3)
    copy_over("edges", "vertices", components=2)
    copy_over("loops", "vertex_index")
    copy_over("polygons", "loop_start")
    copy_over("polygons", "loop_total")

    dst_mesh.validate()
    dst_mesh.update(calc_edges_loose=True)

    dst_ob = bpy.data.objects.new(dst_mesh.name, dst_mesh)
    dst_ob.location = context.scene.cursor.location
    context.scene.collection.objects.link(dst_ob)

    if bpy.ops.object.select_all.poll():
        bpy.ops.object.select_all(action='DESELECT')
    dst_ob.select_set(True)
    context.view_layer.objects.active = dst_ob

do_copy_pure_geometry()