My late wife and I had our first European cruise on Passion May 2018. We had previously done mainly sea cruises but also cruised Mississippi, Yangtse and Murray River (Australia).
We did all the included tours and loved them. We were also keen Geocachers and used free time geocaching which took us to many interesting places, architectural, historical and scenic, many places not usually seen on tours. Great if you like walking but using E-bikes is an option.
On thing wanted to see, but missed in Budapest due to lack of time, was the underground hospital.
Another cruise is on the cards for next year so may get to it yet.