This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 凲 is uncertain. It visually combines ⺇ (a wind-related enclosure) with 兼, but the original meaning and component function are unclear.
Since the meaning is unclear, picture the wind enclosure ⺇ wrapping around 兼 (concurrently), as if the wind carries multiple things at once—but treat this as a placeholder, not a real meaning.
For カン, imagine a can (カン) being blown by the wind inside the ⺇ enclosure: the can rattles around, and you remember カン.