What's with Ei and Peruere's Domain Expansions having the Crimson Moon all over?

Ei's domain represents her inner consciousness and thoughts. The moon in her domain is likely due to her trauma of witnessing Makoto's death in Khaenriah, where the crimson moon is. While Arlecchino is a descendant of the Crimson Moon dynasty from Khaenriah

not sure if ei's is crimson moon. arlecchino is said to be related to khaenri'ah's crimson moon dynasty.

because genshin team out of idea, they just copy + paste and change the colour