The best thing I can say is you have a really addicting loop here, and everything from this game is basically stuck in my head!
The best part is how you set it up so their story progresses. For a sequel, not for this, Bella should do more tavern things. One thing that could be done for each hero along those lines, is “what’s it to ya?” especially for the heroes that level up quickly and start to get ahead of themselves.
If I were to suggest something to trade your time, I would show up to 4 heroes at the tavern at the same time which you have to select instead of the queueing system. That would have another potential peril opportunity of heroes feeling Bella’s tavern is too crowded.
If I could have 1 new feature, it would be a “hold slot” like Tetris now uses where Bella would send only 1 hero on a “Personal Quest” which that would be a side quest with another ending, however obviously only on the easier difficulties. For the hardest difficulty the other barkeep (or a spy) should visit for a really hard side quest instead.