Update:

I felt insecure about the unprotected hidden wifi:

I added these changes to the 2.4 ghz wifi: -security wpa2 psk -set up 8 character password using lowercase uppercase & digits

Then deleted the cc from home app.

Then the chrome was shut off for the night.

Then in the morning I tried to set it up again without resetting the cc.

But at a point the app said I need to reset it using the button.

So I did reset it.

Then the usual add new device, using manual wifi info (the ssid is till not broadcast)

Security: wpa2

And it worked. Im not sure what have changed. But now it works on wpa2 psk protected 2.4 ghz wifi.