I think you should reinstall Appium as they cannot find it:
npm install -g appium && appium -v
Make sure you install correct Node js version
Check the Appium Path in KS: Window > Katalon Studio Preferences > Katalon > Mobile > Appium
Check PATH Environment Variable: Ensure that the directory containing the Appium executable is included in your system’s PATH environment variable. This allows your system to locate the Appium executable when you run the Appium command.
You will likely also have to install a version of appium supported by Katalon Studio instead of the most up to date one unless you want to use the proof of concept one which still has a few issues with it. To do that when installing appium you will need to run
npm install -g firstname.lastname@example.org
If you install appium 2.0 or above you will need to use a different version of Katalon Studio or use remote execution to run:
Yeah sorry I am not exactly sure what features are paid features and which ones are free features. It seems weird that running a script shows as a paid feature. Are you making sure to select Android execution when attempting to run the test using the dropdown on the play button?
Great to hear that you have been able to install Appium. Please double check this: Trial and Free Plans | Katalon Docs to make sure you are valid with Free plan. If you have passed 30-day-trial or over the acceptable number of quota, you need to pay for more usage. Thank you!