Hi @jbs_sf. The "SparkFun SAMD Boards" platform (AKA "core") has a dependency on the tools that are installed when you install the "Arduino SAMD Boards (32-bits ARM Cortex-M0+)" platform. So you must install both those platforms.
If you don't install the "Arduino SAMD Boards (32-bits ARM Cortex-M0+)" platform then the right version of arm-none-eabi-gcc tool isn't installed and you get this error message.
Once you have installed the platforms, you will use the Tools > Board > SparkFun SAMD Boards > SparkFun Qwiic Micro menu selection in Arduino IDE, just as described in SparkFun's instructions.
If you would like me to provide instructions you can follow to install the "Arduino SAMD Boards (32-bits ARM Cortex-M0+)" platform, just tell me which version of Arduino IDE you are using (e.g., "2.0.1")? The version is shown on the window title bar and also in the Help > About dialog.
It does not make a difference.