My solution works well enough for me and is much easier in RTF than MD.
The only way I can think of getting equivalent function in markdown would be a set of buttons (or right click options) which would automatically apply the desired html style. If a system like that were set up then it could be used for a wide range of other text styles such as text colour, size and font.
And they would need a much expanded set of right click options or a ribbon - which has already been requested.