when the guest gets redirected to the splash page, the user role will be "Splash Profile 1_#guest#_ ", then after the guest user accepts T&Cs, and authentication is successful, it should be put in the user role which is the same as the name of the SSID by default.
so what is the user role the guest user is put into after?
you can use this command to check it
"show clients"
Also you can use this command to check if the authentication is successful or not, this is important to be able to troubleshoot.
"show ap debug auth-trace-buf mac <mad-addr>"