Thank you Ari! This is incredibly helpful.
Quick tip for Rider users: If anyone else is having trouble with watching globals, here is what works for me:
@ ALREADY PREPROCESSED @{,,<ModuleName>.dll}<VariableName>
For GPlayInEditorContextString it looks like this:
@ ALREADY PREPROCESSED @{,,UnrealEditor-Engine.dll}GPlayInEditorContextString
Simply add the string above as watch. The <ModuleName>!<GlobalVarName> notation does not seem to work in Rider.