Pre-Covid the three most often suggested hotels with port shuttles were the Embassy Suites MIA, La Quinta East and Hampton Inn Blue Lagoon. I would call all three to verify that they still offer port shuttles. All three are located near MIA airport - you will not see much of Miami. Of the three, the Hampton Inn is in the best location with nearby shopping and dining.
Or skip the shuttles, use taxis or Uber/Lyft and stay downtown with lots of local dining, shopping and nightlife options. Your call!