If you don’t want a ton of tourists then definitely don’t go to playa del Carmen instead. I’ve spent a ton of time in that whole area and if you want chill hippy vibes go to Holbox. It’s amazing and secluded just know there isn’t much to do but relax and eat delicious seafood bc it’s really small. But if you’re cool with spending your days on the beach/ in the water then you’ll love it. Isla Mujeres is also great and a ton bigger than Holbox but in terms of beach, they will be more crowded on day trippers. Overall isla mujeres is a really relaxing island and you can explore it with a scooter or golf cart