Musescore 4 - formatting text in System and Staff Lines

In Palettes > Lines, I discovered System and Staff lines. These look very useful, but is there any way to change the appearance of the text such as font, font size, or characteristics such as bold, italic, etc.? The only available style properties seem to be for the line itself, not the text.

This is what I tried:
1. Click on a rest or note.
2. Select Palettes > Lines> System text.
3. The line appears in the score, with the word System. Click on it.
4. From the side tabs, select Properties. There are style options for the Text LIne. For Text, there are offset options, and places to enter the text values, but nothing for text format.
5. From the top menu, select Format > Style > System text. There are options for Location, but not for font or size.

However, if I add System or Staff text through the menu system, such as Add > Text > System Text, I can change the appearance of the system text. But then, I don't get the line.

I'm using:
Musescore 4.0.2.230651546
Revision: db37c6d

Mac Mini M1, 2020, 8GB memory
macOS: Ventura 13.3.1 (a)