I've sailed Alaska 3 times and am returning July 2023, it can be a very active trip! I've also sailed Europe several times, both are amazing but I vote Alaska for weather during this August. As posted above, I'd also do the land portion on my own.
In Alaska the ship isn't the focus, it's 100% about the scenery.
Tours are very pricey, much more than Europe and I do suggest getting out of the port areas for a much better experience.
Only you know if you care more for wildlife, mountains and glaciers or cathedrals, sunsets and ancient architecture.
Alaska is truly special!
Patty