Is YFNSM a branch of a different universe?

* a branch or

So I believe a timeline is a branch in the same tree/loop and one black hole, and a universe is one black hole. So What If...? is different timelines within Loki's tree, but Fantastic Four, and X-Men, and 838 are different universe/black holes. So is Your Friendly Neighborhood Spider-Man a branched timeline from the MCU or a different universe.