Set keyboard type
You can change the keyboard type (ANSI, ISO, JIS) from Virtual Keyboard tab.
About ISO layout specific keys
When using an ISO layout, the characters produced by ISO-specific keys (such as § and ±) may not match the symbols printed on the physical keyboard. This can occur because macOS swaps these keys under certain conditions in a way that does not align with how the Karabiner-Elements virtual keyboard handles them.
If this occurs, enable Swap ISO layout-specific keys under Devices.