There are several messages in the logs such as the one below, linked to disconnects:
- disconnected due to excessive missing ACKs.
For this, I would like you to try the following. Login to router's WebUi, navigate to Network -> Wireless. Edit 2.4GHz interface settings, switch to Advanced tab. Set Station inactivity field value to 36000 and disable Disassociate On Low Acknowledgement option.
Otherwise, could it be that 2.4GHz range is congested with other nearby access points?
Do disconnects happen to all devices at once or each device separately, as no disconnects of all the clients at the same time is not seen in the logs.
Do you have stable mobile network connectivity, when devices experience disconnects?
Does the same apply for 5GHz radio channels?
What is the environment, the router operates in, are there any obstacles, thick walls, which could prevent signal propagation?