How can I create a tablature for diatonic accordion in musescore 4

Hello,

In musescore 2.X I could easily add the key numbers to the score. In musescore 3 it didn't work anymore and I didn't use it anymore. But musescore 4 has now been extensively modified (improved) and that is why I want to use it again, but I am unable to add an extra line with numbers above it.
Has anyone found a solution for this yet?