Restricting which devices can use internet after failing over to backup internet

I am looking to add a Mikrotik wifi router configured to use my cell phone hotspot as a backup on my UDM Pro. Does anyone know if there is a way to limit the traffic to just my work laptop and essential devices so I don’t blow through my cell phone data?

With mikrotik, use the QOS. There are serval youtube videos about this or I can help with use.