We also liked Horseshoe Bend and Antelope Canyon, although the Horseshoe Bend rafting tour is kind of slow and long. We did a kayak tour on Lake Powell that our tween/teen liked the best out of everything we did through this outfitter. They were took us to these rocks where we could jump off. It was really fun.
https://lakepowellpaddleboards.com/shop/
Also, stop and have lunch at the Bird House.