When Kiosk Browser is installed and configured correctly, it becomes a "Device Admin" which stops the normal uninstall process from working.

To Uninstall:
Go to Android Settings > Security > Device Admin Apps (on Samsung devices Security > Other Security Settings > Device Admin Apps)
Untick Kiosk Browser
Uninstall via Settings > Apps > Kiosk Browser > Uninstall

Updated on: 07 / 04 / 2021