I just read your request. I had to research "vinculum" (overbar, overline).
Some thoughts .- perhaps the simplest - why not just create a small rectangle, convert it to a path and resize to fit with the text size you are using .and then duplicate it and move it above the other characters you are using. Let this serve as your "overbar".
Then further resize (stretch) as needed.
Next thought .- research fonts that focus on mathematical symbols, including the vinculum bar, and add that font to your fonts directory, and use it. Many fonts ( sometimes referred to as dingbat fonts) offer many unique and specialized characters.
See this link - you can type in what you wish. Then use the mouse to "paint over" the overline result, copy it and paste it into word processors such as NotePad. From there, you can copy and paste it into Inkscape.
Beginners' Questions Can Inkscape type the vinculum symbol?
Inkscape.org
There is difficulty expressing mathematics on Inkscape. The text tool does not support the vinculum bar or dot notation.
Copy and paste appears as 0.¯5 or 0.5
The work around is two lines with underscore from above. _
0.5
Inkscape can become more educational having the full list of mathematics symbols.
Thank you kindly
I just read your request. I had to research "vinculum" (overbar, overline).
Some thoughts .- perhaps the simplest - why not just create a small rectangle, convert it to a path and resize to fit with the text size you are using .and then duplicate it and move it above the other characters you are using. Let this serve as your "overbar".
Then further resize (stretch) as needed.
Next thought .- research fonts that focus on mathematical symbols, including the vinculum bar, and add that font to your fonts directory, and use it. Many fonts ( sometimes referred to as dingbat fonts) offer many unique and specialized characters.
See this
https://www.fileformat.info/info/unicode/char/203e/fontsupport.htm
See this link - you can type in what you wish. Then use the mouse to "paint over" the overline result, copy it and paste it into word processors such as NotePad. From there, you can copy and paste it into Inkscape.
https://fsymbols.com/generators/overline/
And I found these links that should prove helpful in using unicode within Word and other word processing programs.
(You can copy from Word into Inkscape. And I think, from Google Docs into Inkscape.)
http://wordfaqs.ssbarnhill.com/Overbar.htm
http://wordfaqs.ssbarnhill.com/CombineCharacters.htm
Google Docs
https://smallbusiness.chron.com/putting-bar-over-letter-google-docs-67273.html
https://equation-shortcuts.notuom.com/
See .this
https://sites.psu.edu/symbolcodes/windows/charmap/
You can also do this in Excel, and then copy from Excel into Inkscape also. See ...
https://www.quora.com/How-do-you-overline-in-Excel
https://www.excelbanter.com/charts-charting-excel/116771-overline-excel.html
Perhaps others will have better ideas. I trust this helps you. Have a great day.
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https://fsymbols.com/generators/overline/
You may have seen this: https://inkscape.org/~jcwinkler/%E2%98%85textext