@fyd 

Hi, welcome to our community.

According to the data from the official website, the ideal number tested from the lab is up to 100.

While in actual usage, quantity of connected devices are not guaranteed and will vary as a result of network conditions, client limitations, and environmental factors, including building materials, obstacles, volume and density of traffic, and client location.

According to your information, it is suggested to clean up the offline client list regularly to avoid MAC address stacking that leads to resource consumption.

Also, if the number of your client devices is high,  you may consider adding Deco units.

Thank you and best regards.