This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
坥 combines 土 (earth) with 且, but the exact historical development is uncertain. It may have originally referred to a type of earthen structure or mound, but this is speculative.
Since the meaning is unclear, focus on the shape: 土 (earth) beside 且, like a mound of earth piled up. This may help remember the character even without a fixed meaning.
For ショ, imagine a small show being performed on an earthen stage: show -> ショ, and the 土 (earth) component hints at the ground.