This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
祾 combines 示 (altar, spirit) with 夌, which likely contributes sound. The exact historical development is uncertain.
The left side 示 suggests something related to spirits or altars, but the overall meaning is obscure. Picture an altar with an unclear offering.
For リョウ, imagine a spirit at the altar whispering a soft 'ryo' sound: ryo -> リョウ.