I have a question I need so help

I’m so confused about this whole Earth-199999 or Earth-616 debate. People on Twitter/X keep saying that this is 616 Wanda, but the comics have always been Earth-616. Even in Spider-Verse, they called the MCU Earth-199999.

But then it gets confusing because in Spider-Verse, Peter B. Parker is also from 616, even though we know that the comics and MCU are not canon to each other at all. The MCU is a completely different universe, and so much stuff is different.

When did people start calling Earth-199999 Earth-616? Sorry if this is a dumb or over-asked question—I just found out about this because of an image (I don’t know where it’s from or what comic it is), but yeah, that’s why I’m confused.