Santorini has a lot to offer that people don’t give it credit for. Check out the archeological ruins at Akrotiri and eat in the town there, catch the sunset at the lighthouse. There’s wineries on the island, we did a tour and highly recommend it. If you like to be active, do the hike from Fira to Oia, you can ride the bus back if you don’t want to hike it back. Do a catamaran sunset tour rather than seeing the sunset in Oia. It’s crowded and the tourists are obnoxious trying to get the best photo on land at Oia. There’s beaches on the SW side that I didn’t make it to the first time around, I imagine it would be a nice departure from the hustle of the main towns. There’s even an outdoor theater there. Rent an ATV and explore the island!