Sorry if this is duplicative, but I don't think we should be seeing "This formula uses scope, which is not presently supported for evaluation" for formulas involving ThisItem.(fieldname) in power Apps Studio.
Perhaps I'm missing some technical reason, but if you shape the formula in a way that has a text result, you can easily see what the result would be in any control that displays text. So obviously Power Apps can access the data, it just refuses to show that in the evaluator view. Could this please be resolved? It's a hassle to have to make throw away controls just to see what the result would be when involving ThisItem.(whatever).