First question : Does the Robotframework AppiumLibrary support the Appium driver for MacOS?
AppiumLibrary is only a set of method that could be imported on .robot files, this set of methods is written using appium-python-client, so what is able to be done with appium and python could be done with Robotframework-AppiumLibrary
Second question : it’s only possible to use AppiumLibrary to automate MacOS desktop applications run on MacOS
Yes , and do not even deserve to be given a try