Not quite the same thing as One World Religion. Christians should be one in spirit. Outward things can be a reminder or a manifestation of such.
Also agree Easter should be tied to Jewish calendar. No replacementarianism.
It makes sense that it follows Passover rather than the first Sunday after the first full moon after the first day of spring.
A lot of people don’t know how it’s determined and when I tell them that, their eyes just sort of glaze over.