Add an option to Transpose chord symbols only
I recommend that MuseScore enable the “Transpose chord symbols” when the current selection contains only chord symbols.
I find it surprising that MuseScore doesn't offer independent transposition of chord symbols, particularly when the Tools>Transpose dialog houses a checkbox specifically for that purpose.
The simple solution is to enable the “Transpose chord symbols” even when the user has only chord symbols selected. Then run the existing methods which are fully capable of performing the chord symbol transposition. (Currently the checkbox is enabled only when staff notation is selected, and checking it only allows us to NOT transpose chord symbols while transposing staff notation.)
Ironically, with only chord symbols selected, MuseScore disables the dialog's option to transpose chord symbols—as if it's trying to protect against some unwanted outcome.
In the MuseScore 4.0 alpha, as of 05-20-2022, the Transpose dialog is unchanged from v3.6.2