Getting a list of supported resolution action is something playmaker doesn't come with, but you can get it through 'Screen.resolutions' if you did it in code.
It will store everything into a long array variable.
Here's the Unity reference for it:
https://docs.unity3d.com/ScriptReference/Screen-resolutions.htmlI just ignored this by simply allowing predetermined generic resolutions, like:
1280x720, 1920x1080, 2560x1440, etc etc.
And then use the SetResolution from the forum post you linked to set the resolution.