Tape vs screw joining 4" duct
Tape is not a mechanical fastener. It is a sealant. It is not acceptable as a way of connecting duct. The options are screws, hose clamps or zip ties depending on temperature.

I have used hose clamps to connect all the metal duct on my dryer exhaust. For the bathroom fan it will be a combination of screws and zip ties as there will be some insulated flex duct.

Also when sealing ducts you may only use one method of sealant either mastic or tape. You can't use both. They aren't rated or listed for use together.