@Kevin_Z yes, all right LEDs are on, of course including 2.4 otherwise I would not see my 2.4 in my list on phone, notebook, TV etc. you can see I made also Guest 2.4 net and shows same problem

@Jan_archer Did factory reset, same problem. 5g fine, 2,4g has this: Network_Selection_Disable_Association_Rejection

2 weeks old router Archer AX10 5G works great but can not connect to 2,4G WiFi all our 3 phones and two notebooks can not connect, reboot does not help in WiFi settings in phone you can find this...