@iwrk4dedpr
Not quite sure about the ISP account?
You do need to have a TP-Link cloud account created in Kasa so you can then add the switches. The way the app works when adding a swtich it that it will automatically enable the remote control for you, and that feature is not visible in the switch.
What you can do is to go into your router and block internet connectivity to the devices. What will happen is the switches will show as "local only" in the Kasa app. So even if there is no internet connectivity with them, local control will still be possible.