Perhaps I’m not seeing something here, but while it has the same number of steps, I don’t understand the need to complicate things by creating a new layer.
See if you find the following method both more logical, and universal.
Start with your filled circle, and then type out your text on it.
Select the text.
Click on ‘Object to Path’ in the Path menu, which converts the text to a ‘group’ of paths.
Click on ‘Ungroup’ in the Object menu, then click on ‘Combine’ in the path menu, which turns them into a single path.
Select both the new path and the filled circle,.
Click on ‘Difference’, in the Path menu, and you have the object you require.
