First time in Morocco - help with trip planning

Hi there,

I will be going to Morocco for the first time this Christmas with my partner and would like to ask locals and/or experienced travellers for some tips and tricks.

We are arriving on Sunday 21st December and flying back early morning on Sunday 28th December. Both flights are from and to Marrakesh.

How to make the most out of it, if we want to see Marrakesh, Casablanca, Rabat, Chefchouen and also Sahara Dessert (Fez and then Merzouga)? What would you recommend as the best route?

We will definitely rent a car (at least for the part of the trip) and drive on our own. Any recommendations here, from where to rent the car and what to be aware of?

Also tips for places to visit and not to miss are fully welcomed 🙏

Thank you very much in advance to everyone.