I’d say increase your hearthling count and bring on the kobolds without modding for xp. Make a save and call it “release the kobolds” as a reference.
If you focus on getting a Cleric out as fast as possible, you’ll be able to handle anything within this range of difficulty with some amount of combat tactics. I prefer to single-target my mobs which gets around the combat bug of classes wandering off and trims down the packs faster. Maybe separate the level 1 footman to another group and let him sit in the base or demote to worker as you don’t want to spread the xp out too thin.
The difficulty has been adjusted from my play experience and what I can see in the files. There’s a number of changes under \stonehearth\data\monster_tuning that take some bite out of kobolds. I didn’t notice the monster_tuning folder earlier and it uses mixins to add to the mobs. They did make some xp changes for some things in here but the few random files I’ve look at have been increases to xp. The evil little Kobold archer specifically has 150 less HP, and a decrease in muscle which should mean slightly less damage.
Looking at the campaign settings for when you should start seeing certain random encounters, after day 25 and hearthling count is between 15 and 23 you’ll get the “insane” raids. Not the best name as they aren’t that bad. Kobolds, Golem family, Entlings and Ogre’s come out as trash mob encounters. For the Kobold’s specifically, that’s 2-3 of them and 2-3 wolves.
If you’re curious to see what will come at you and when, you could try having a peak within stonehearth\data\gm\campaigns. Goblin_war and orc_war are the main campaigns and ambient threats are all the random encounters. The folder \stonehearth\data\gm\campaigns\ambient_threats\arcs\trigger\ambient_threats\encounters\trash_mobs\raid_difficulty is where Kobolds and other random spawns are pulled from.