What I’m really interested in is monospaced text within a single line which containing other BBCodes.

Do you have an example for what to use this?

This one... (have a look at the 'pseudo-formula': inlinecode, italics, superscript).
I'm also using it for references to footnotes (see here - inlinecode & superscipt).

Do you want to use monospaced text within a line of regular text?

Yes...