Hi@Shiro0,

May I know if your network topology diagram is as follows:
Cable modem—router)))((( client devices
Note: — stands for wired connection,  )))((( stands for wireless connection 

How often does the SSID disappear or disconnect?

When the SSID disappears, are the wireless LED lights off or in the normal on state? Is the network of the wired device still running normally?
Do the SSIDs of different networks, including guest network and iot network disappear or disconnect at the same time?

• Please try to change to different SSIDs and compare 2.4G and 5G separately;
• Please select the channel manually: 2.4GHz recommends 1/6/11, 5GHz recommends 36/149 ;
• Please turn off the DFS channel;
• Please adjust the placement;
• Please assign fixed IP to key devices;
• Please reduce the number of device connections for comparison.

If the issue persists, please collect system log and Tether APP log, then send logs to can email support.forum@tp-link.com, attaching [Forum ID 783388] and details, and we will have a dedicated person to assist in analysis and follow-up.