This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
幜 combines 巾 (cloth) with 景, which likely contributes the sound. The exact historical development is uncertain.
The left side 巾 suggests cloth, and the right side 景 suggests a scene or view. Imagine a cloth used to cover or display something, but its exact meaning is unclear.
For ケイ, picture a cloth (巾) covering a scenic view (景) at a kayak race: kayak -> ケイ.