Repair Rhino File for 3D Printing

My architectural model was built in Rhino 8 and every time I load it into the Bambu Studio it throws non-manifold errors that stop the slice. I need the geometry cleaned up so the structure looks exactly the same but becomes a single, watertight solid that slices without complaints... (Budget: $12 - $30 SGD, Jobs: 3D Modelling, 3D Printing, Rhino 3D)