Sea cruises have "all-inclusive" just on food. It doesn't mean you cannot eat locally.
But some comments:
Attention to "Tour Europe". If cruise do just EU ports, you have taxes included on all drinks. Just by having a port outside EU will make cruise cheaper.
late departures: 8-10pm is not enough to have dinner outside. South Europe will eat later, or you will just eat like a tourist, nothing really local.
late departures means to navigate just short. Cruises doesn't want to cruise fast on night, for comfort of passengers, so or you will have to go just on nearby ports, or having a lot of sea days (so you should eat in the ship).
you are looking something that it is not really what we mean for cruise. So you will get difficulty to find something for you. Cruise lines are industries which will provide entertainment, and way to spend money onboard, so they are not design to be accommodation and transport: they are looking for people who want to enjoy being onboard (and so spend onboard).
You may find something for e.g. Greece islands (smaller boats), or you should check river cruises (depart late on evening). You may look yacht clubs (google): people needs to make miles to get a better license, so often you will find them looking for some passengers to share some costs (but they will not cook for you, so you go cheap, and no extra).