Special characters in lyrics

I am writing sheet music for a song in the Lingít language. Some letters in this language are underlined. The underline is a special character that makes a slightly shorter line than if you use a text editor to underline one letter. I have a keyboard shortcut that allows me to write these characters. For example, the syllable in the song is "gax̱". In unicode the x underline is:

x latin small letter x
̱ combining macron below

When I type this character in MuseScore 3, it shifts the underline over to the right rather than being centered under the x.
Is there a way I can get it to be centered again? Or can you please fix this? Using the regular underline is not ideal as it is not the way the language is supposed to be written.
(the letters are colored because we are using the Figurenotes plug-in)
Thanks