This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 卛 is uncertain. It visually combines 䜌 on top with 十 on the bottom, but the original semantic and phonetic roles of these components are unclear.
With no clear meaning, picture the top 䜌 as a tangled knot of threads and the bottom 十 as a cross-shaped tool trying to untangle it—perhaps suggesting leading or guiding, but this is speculative.
For ソツ, imagine a tangled knot (䜌) suddenly snapping apart with a sharp 'sots' sound: sots -> ソツ.