You insist that the word “Sunday” has ‘nothing to do with Sunday’. What is your evidence for that claim? It seems to me that “Sunday” and ‘Sunday’ have a lot to do with each other!

Monday - day celebrating the Moon

Tuesday - day celebrating Tyr (Norse god)

Wednesday - day celebrating Wodin (Odin) (Norse god)

Thursday - day celebrating Thor (Norse god)

Friday - day celebrating Frigga (or Freya) (Norse god)

Saturday - day celebrating Saturn

Sunday - day celebrating the Sun

Dividing peoples’ lives into seven-day sections (weeks) goes back at least four thousand years…to the ancient Babylonians and Sumerians.

The habit of linking days of the week to various Norse or Roman gods goes back a couple of thousand years. The Romans called Sunday “dies solis” - Latin for “day of the sun”.