Common Time and Alla Breve in Text

Select a note or rest in the measure to which you want to attach the Common Time/Cut Time symbol.
Click Add / Text / System Text.
Click the button to Insert special characters.
On the Special characters dialog, click the Musical symbols tab.
From the categories at left, select Time signatures.
Click the Common Time and/or Cut Time symbols from the list to add them to the text field.

You'll need to experiment to get size and orientation the way you want it. You might have to put them in separate text fields?

Ah that Schubert! It's what I had in mind when I engraved the following, back in 2020, using Musescore 3.x. How I did it:
1) On the time signature palette, create a custom time signature which has an actual duration of 4/2, but an appearance* of "¢". Use that to set your music.
2) select the first note (or rest) in the measure.
3) Go to Master Palette (Shft+F9)-->Symbols-->Time Signatures., and click on the "¢" symbol >>>Make sure that you choose the font (Leland, etc.; I used Emmentaler) that you are using already, otherwise the two "¢"s won't match.
4) Move the second "¢" into position. You might want to do this as a final step in the engraving, as any subsequent changes in the layout may throw all your hard work awry.

*As I said, I set this in 3.x--It appears to open fine in 4.2; although, if you don't have Cardo (text) font installed on your computer, some of the text elements may not display correctly. However, I noticed that in 4.2, the "appearance" field under "time signature properties" for creating custom time signatures does not have options for "c" and "¢". (It does have those options for modifying existing signatures, albeit locally.)

Oh, and BTW, I still use 3.6.2 for score set up and note entry (I guess I had just become so comfortable with it), then create a copy of the file and use 4.2 to do spacing and layout clean-up.