I run into an issue where i needed to get the optionset value label , Property was available through the old CDS connector and the Dynamics 365 Connector.
So to get it from a List Records action you can use a compose data operation with the expression below:
items('Apply_to_each')['fieldschemaname@OData.Community.Display.V1.FormattedValue']Replace fieldschemaname with your fieldName and Apply_to_each with your loop name.
To get it from Get Record action you case use:
outputs('Get_Record')['body']['fieldschemaname@OData.Community.Display.V1.FormattedValue']Quick one but very useful!
MG 