How do I swap out the default UE5 mannequin with a marketplace asset?

What is the workflow to do this the correct way? I see only tutorials on how to retarget animations but nothing about the mesh itself. But what if the project is already built using the UE5 mannequin? And the asset I bought uses the UE4 skeleton?

Do I somehow retarget the mesh? Or do I retarget the entire Anim BP to the marketplace asset skeleton? I’m very confused on the right workflow for this.