OK. Yes, it is plausible that buggy 5GHz firmware might affect 2.4GHz radio...
I have found evidence in some other threads that ath10k indeed affects 2.4 even if it should not to:
I am now testing "backdated" ath10k driver so we will see how it goes. If nothing happens within 2 days then it works! And if it is stupid but works then it is not stupid!
