This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
傃 combines 亻 (person) with 素, which may have contributed sound. The exact historical development is uncertain.
A person 亻 beside 素, which can suggest plain or elemental. Without a clear meaning, picture a person facing something fundamental or plain.
For ソ, imagine a person (亻) sewing (ソ) plain fabric (素): sew -> ソ.