yes, i've been there and i've looked for some config variable to put in the hostapd config but so far its not clear to me what should be there.
Is it possible for you to check if your iw list output has an airtime fairness line and, if so, what might be in your hostapd config file that is not in mine?
Note i have built and tested the ath10k-ct driver with and without commenting out support for "airtime fairness" here.
There is no difference for me either way.
This in combination with my iw list output makes me suspect "airtime fairness" is not enabled in the ath10k-ct 99x0 firmware. Before I ping @greearb, I want to confirm that it is working for others.
I'll try playing with the config variables you posted above and see if shows up.