I mean. We don't know that Qrech isn't a Daemon as part of a Tzncheeh scheme to break the conspiracy of silence.
We've also embedded corruptible humans into a dwarf Karak which could set the groundwork for a betrayal that could severely shake the Empire/KA alliance.
But also Chaos is a lot less powerful and omni present than it is in 40K. The lowest point Omegahugger brought up was prior to us getting the Belt. They just didn't know how far Mathilde would go, and it takes a lot more effort from the to corrupt people when Daemons can't just whisper in the ears of psykers.
The Lamians where controlling us at the start so they would have had to compete for control. After Abelheim gave us the information to dismantle them, we went on a march to retake K8P which is a terrible environment to try and induct us into a cult. After that the humans who weren't Dwarves, Halflings, possibly mind warped by Kragg and the rune of Dwarfiness or pious Ulricans left so the gods where left with the hardest people to try and make a cult out of, which will have limited Chaoses abilities to do something then.
Opportunities are less frequent and not all the great than we might think.