This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The historical origin of 啚 is uncertain. It may be a variant or component form, but its development is not well documented.
With no clear meaning, picture 啚 as a mysterious container: a mouth 口 over a box 㐭, holding something unknown.
For ヒ, imagine a hidden he (ヒ) sound escaping from the mysterious box, like a secret whisper.