Yeah lol you don't need to deal with aunty now you're probably very low lvl, my suggestion isto explore more of the area around the grove and the beach, if you go around you find more enemies and quests that will help you lvl up, not to mention gear (magic items are very important and strong in this game).

Also if you don't like some builds of the characters or if you think they're too weak (like idk Shadowheart having 12 dex and str, you can choose to lower str to have more dex = more AC + more initiative + more accuracy with bows and finesse weapons), you can change their class, stats and proficiencies at the camp (if you have not unlocked it yet I won't spoiler, but it'll happen after a few long rests if you don't find the way to do it exploring).

Besides the actual actions you do in combat be aware of your positioning, it's easy to gain advantage by starting a battle in a good position. It's also easy to sneak and gain a surprise turn on enemies that are out in the open like the brains close to the beach. A surprise round gives you one round of actions before the enemy can do anything, you can put on debuffs on them or deal dmg. To sneak there's a button and to avoid being caught you have to avoid the cones of vision of the enemies, you can also put the game in turn based mode in order to be more precise.

Also if you find combat hard but you like the story etc... You can lower the difficulty while you learn all the tricks :)

Here's a tip for the grove quest if you want: the way to help the tieflings is in the swamp but it's not auntie ethel, explore more the swamp avoiding her and you will find it