Superstition annual tax return

Hello community, I have to do my first tax return next year because I was finally able to cancel my BaV and have it paid out this year. Now I have only received feedback from my friends along the lines of “If you submit a tax return once, you have to do it annually”. After my own research, I have come to the conclusion that I don't have to do this (I am employed normally and have no other taxable income). Where does this myth “One tax claim come from?”