I have split the 2.4GHz and 5GHz channel but 5GHz channel not showing up on my wifi automatic detection.
and yes, my devices are capable of 5GHz.
I have tried the smart channel and specify manual channel.
Why is it not showing?
As you don't have a SH2 which hub do you have
Might be worth turning off, saving & then turning on again. Did you accept the suggested SSID for the 5GHz or create your own? If the latter did you use any unusual characters?
Only other thing would be a factory reset & if still no show, it's likely faulty.