You can autoresolve battles by selecting "let your second-in-command take care of it", but only in pursuits as the aggressor (which isn't really what you're looking for, as that's one specific form of combat that, especially if you're not able to compete in the combat arena and thus build up your wealth and threat level very well in the first place, you won't be initiating very much).
Unfortunately... I mean, right now the game is kind of feature-complete on the combat side, and you just joined (presuming you're new-ish) when the campaign/strategic level started to get fleshed out. For the most part, it's not really wrong to say the campaign acts as a setpiece to get you from battle to battle, at least as of the current build.