About the goal: I think there are already good games out there that show you how this could work. For example in many autobattlers you have async multiplayer with a leveling/ranking system. So you play until you either get 10 wins or loose all your lifes. then you either rank up or down and get more difficult or easier oponents in the next run. I think this sort of dynamic difficulty could also work without the async multiplayer. You just make the oponents stronger for better ranks and weaker in the lower ones.
For the Fight listings I am not so sure. One Idea I have would be to add a time limit to the fight so that you need to finish them off quickly. This seems like an interesting challenge as it might be difficult to guess beforehand if you can win. Also it might just cost something to do the fight. The fights could also be much more difficult to just make it harder to win them. This would be kind of like the mechanic of “mini-bosses” in a lot of roguelike games. They are high-risk high-reward. If you loose the fight It should have a negative consequence like maybe loosing one of your teammembers.
The idea of having many units is great. I would wait with adding them however. I feel like the current units are already interesting and allow for some interesting strategies. I would first concentrate on fixing the issues and only then add more content.
Again I think you should keep working on this. I like it a lot. :)
