This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
圚 combines the enclosure 囗 with 貴 inside. The exact historical development is uncertain, and the character is rare in modern use.
The enclosure 囗 surrounds 貴 (precious). Picture a precious item locked inside a box, but its exact meaning remains unclear.
For カイ, imagine the precious item inside the box is a kite (カイト): kite -> カイ, and the box keeps it safe.