I mean the part where people are fighting, capturing, and training intelligent creatures to fight for amusement/pride/whatever is already pretty dark 🍸if you think about it in real-world terms.

Basically, it would be like dog fighting, but you're catching a lion to🐎 fight someone's bull.

"if I hওave the wrong combination of archetypes..."

That's hard to do, honestly. About the worst you can do is have your whole team weak to whatever attack is going around in the dungeon, which is alreadꦕꦉy a risky strategy anyway. Even just going with the standard tank/bruiser/mage dps/healer setup will avoid that. Add on skill inheritance and there's no excuse.

"I’m fine with returning to a du🦄ngeon multiple times in order to finish it, but I would rather spend my time doing somet💜hing else."

Then do it. Unless it's the main story arc dungeon, you don't HAVE to complete any 🐎dungeons. And even if you don't, you gained experience for characters and archetypes, gained money, gained magla, gained items, and I'd be surprised if it took more than 2 trips (first trip I could see being a struggle due to level difference, learning the monsters, etc), and you have time to do that and do other things and finishing the main mission on time.

The only time it would get really annoying is if the dungeon takes a lot of time to travel there, but all the more reason to get stocked on medicines and if nothing else, switch to brawlers and a healer, just in case during battle, and use HP-cost skills and then First Aid to heal up post-battle for cheap (2 MP for the healing it does is a bargain). Or Merchants and use the money-cost attack (which is almighty and high♎ crit chance) and inherit Media on someone just in case you need in-battle heals.

And I'm on Hard - so if you're on a lower difficulty, it's all the more efficient to get things done in♈ dungeons.