It is a part of Daoist talisman but not an ideograph based on provided evidence. Used with clearly unencodable Daoist signs. This "ideograph" should be rejected by IRG.
Another version of 正统道藏·道法会元

The evidence is very clear, and the context shows that the character is obviously an ideograph. This and the other six related characters complete the set started with UK-20710 ⿱雨⿺鬼☷ (Ext. J draft U+33281), so there is no reason not to encode.

Comment #4937 says "The evidence is very clear, and the context shows that the character is obviously an ideograph". This is truly unbelievable.
The context clearly states that they are parts of axe tailismans(斧符) and should be drawn in the blank side of the drawings of axes(空邊入卦號). I really don't understand why it is obviously an ideograph based on this kind of context.
The context clearly proves that UK-30471 and all other seven ones(including the one in Ext.J draft) are just signs systematically created by adding 雨 and 鬼 to 八卦☰☱☲☳☴☵☶☷. They are created for the tailismans used in special cermonies to ask Gods' help(到處萬神奉行). They are not used in texts and have no semantics.

The UK-20710, which has not formally be encoded, is used in the same way, i.e. being drawn in the drawings of axes. This was also clearly stated in the book 《梵音斗科》. It is just that the whole image of the related context was not provided by the UK in IRG WS2021.
[WS2021-04313]
Whole image:

Evidence the UK provided in IRG WS2021:

It is perfectly reasonable to want to digitally represent a text which discusses how to use particular ideographs to draw talismans, and ideographs which are mentioned in such a text are perfectly valid candidates for encoding. We are not proposing to encode talismans, but are proposing to encode characters which are used in printed text. The fact that a text relates to talismans, or describes how characters should be drawn on an axe or a pair of boots, is completely irrelevant to whether the characters should be encoded or not.