This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 僌 is uncertain. It visually contains 亻 (person) on the left, but the right side is not a common modern component and its origin is unclear.
With no clear meaning, focus on the shape: a person 亻 beside an unusual right side. Remember it as a rare kanji whose meaning is unknown.
For ヨウ, imagine a person 亻 saying 'yo!' in surprise at the strange right side: yo -> ヨウ.