Didn't tried the quest system that is available during the skimishes so far, as my battles were more focused on taking out the enemy.
So i did as those quests are making a storyline to break a bit away from generic 4X gameplay, but as i didn't read spoiler ahead i wasn't expected what happened on one of the quest
one of those quests were requesting me to research librarian and build one, that i did.
The librarian detected a corruption in an IG camp that wasn't existing before and i was tasked to take them out.
That camp spawned right next 3 of my space marines squads that i left at some safe enough distance from an ork "boss tower" (as the thing has 2 tiles of range) from an ork base.
There was a lot of IG infantry squads, a couple of Sentinels and some artillery-like infantry .
My 3 squads didn't lasted long (as the corrupted IG were starting their turn immediately after spawning).
Took a while but i managed to kill them all and move to the next quest that involved visiting 3 specific locations with a librarian, one of them was in an area with an absurd amount of strong critters and a bastion tower.
From there i also noticed it unfortunately managed to to beat the orks by destroying the 2 bases they made in the amount of time it took me to try to beat the current 3 location quest (lost 2 librarians in the insane area that was the 3rd locations).
Hmm, it looks like there some nice quest system, an optional alternate way to win the game (and get some reward from completing each quests), but on small maps it is better to focus on your opponent(s) but maybe on larger map it would be interesting. A bit like on 4X you have different victory condition, not only destroying the AI opponents .
Though having read some spoilers by now, the difficulty near the end of the questlines seems crazy