① The Wi-Fi 6 protocol is only supported by some mobile phones. Please check whether the mobile phones support this protocol.
② Enter 192.168.31.1 management background and check whether "WiFi5 compatible mode" is enabled (location: Settings >>WiFi Settings >>WiFi5 compatibility mode)
Note 1: Some old devices don't support Wi-Fi 6. Signals may not be detected or the connection may not be good.After this switch is turned on, the mode will be switched to Wi-Fi 5 and the related functions of Wi-Fi 6 will be turned off, such as OFDMA, BSS Coloring, etc.
Note 2: You can also see the compatibility mode option in the "App plug-in,Xiaomi Mesh System AX3000>>Network Settings>>WiFi Settings" interface.
Does it help?