I wrote out how I play hard mode here.
Since I wrote this Radient have made hard mode even harder, they reduced the frequency of the attacks in the early game to “make the game easier”. Sounds like it will help, wrong. Now you don’t get attacked as much, so you can’t level up your combatants enough before the harder enemies come around the 15 to 20 day mark.
Another problem at the minute is once you have beet the first goblin campaign there is too much of a difficulty disparity between it and the following ogre raids. E.g the first ogre raids now can wipe you out your 2 footmen, archer and 2 clerics without you killing a single one of there archers or footmen.
Even so I hope it helps.