Don't know what type of router you guys have but some possibilities could be:
Keeps switching to 320MHz channels. Change the Channel Width to exclude 320MHz. (Unless you need it for other devices).
Disable MIMO, and enable MLO, if your router has that option.
If you are using the same Wifi Name for everything. Make sure the wifi encryption is set to WPA3 for everything. Don't have the 2.4GHz & 5GHz settings at WPA2 when the 6GHz settings is at WPA3.