I will be goining to Mexico later in November and will be spending 3 weeks. This is my first time ever in Mexico and my Spanish is extreemly basic but I can manage my way around.

I'm travelling solo and I'm interested in spliting my vacation as: beach (1 week) and culture/adventure (2 weeks). I will be flying into Cancun and out of Mexico City.

Q1)
I'm planning to spend the first week on the East Coast (Cancun) to chill out at the beach and I'm seeking suggestions for planning the remaining two weeks.

I may consider to rent a car and drive around Quintana Roo/Yucatan for about two weeks then fly from Merida to Mexico City. However, I'm not sure if driving around solo would be a safe idea. I enjoy driving but I wouldn't compromise my safety.
Alternatively, I may opt to fly to Oaxaca for a week and then to Baja California to spend another week. Then, I would fly to Mexico City (transit) to catch my flight back home.

Q2)
Since I'm flying out of Mexico City, I have the option of reaching there a couple of days ahead of my flight back to London to explore the city. So far, I didn't get encouraging feedback on Mexico City and I'm hesitant to spend a day there.

"Gracias" in advance for your suggestions and comments.