Legion is not MCU, but personal headcanon of mine is that Switch's father ("Xiu") is a high-ranking TVA agent that created or instructed a variant/"robot" named "Jia-Yi" (translates to "plus one" - Thanks Oliver Bird!) to completely erase the Legion show's timeline.
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Unfortunately the "
Earth-19264" on the Appendix conflicts with that idea. So I could also headcanon that as a branch of a branch being destroyed...Again, not stating anything as fact or requesting anything, just rambling.
Also, personally, I'd prefer if this was Earth-19264:
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