That would mean the "original" multiverse was deleted with everyone on it "dying" or ceasing to exist, and now we are in a new timeline for the Marvel multiverse were Loki somehow controls everything to keep the timelines/branches/universes safe.

Source: https://comicbookmovie.com/tv/marvel/loki/lokis-mind-bending-season-2-finale-finally-reveals-the-god-of-mischiefs-glorious-purpose---spoilers-a207723

The strongest versions of The Rhino from across the Marvel multiverse highlight how powerful this dim-witted Spider-Man villain could be.

Source: https://www.cbr.com/strongest-rhino-variants-ranked-marvel-comics-spiderman/

Through the intertwining miracles of the Marvel multiverse, CGI that can shave off decades of age, and a star whose box office record had been awful since his exit from the MCU, is possible, so Downey returning as Iron Man doesn’t seem too far-fetched.

Source: https://www.digitaltrends.com/movies/mcu-sequels-bob-iger-wrong-about-more-marvel-movies/

To that end, He Who Remains and Kang had the same goals in the MCU and the greater Marvel multiverse.

Source: https://screenrant.com/he-who-remains-more-powerful-stronger-kang-conqueror/

Unlike its 2018 predecessor, Spider-Man: Across the Spider-Verse expands the Marvel multiverse in a meaningful way.

Source: https://www.cbr.com/spiderman-across-the-spider-verse-better-into-the-spider-verse/