“Head of” is a creative solution for the rapid growth and lack of leveling. “Head of” is not a level, but an indication of the oversight one has in the current stage of size and scale. It can be held as helpful to someone at a junior level than an executive level.
It can be helpful to have this title in use during the early phases of growth before needing to bring in more experienced leadership.
There should always be an upfront discussion with candidates about the future growth anticipated and at what stage support would be brought in to help achieve the next phase of growth (e.g., effectively removing their “Head of” designation once the next level leader is hired or specializing their “Head of” title).