Moon Knight Ending Explained -- Where Does Marc Spector Fit In The MCU?

gamespot.com:

The latest Disney+ MCU TV Show, Moon Knight, has concluded its first season--and while we cannot be certain yet if the story will continue in a Season 2 or within the MCU movies somewhere, the finale did leave our heroes in a rather precarious position. Let's take a look at what happened and what it might mean for the future of Phase 4, all while getting into some pretty major spoilers for the whole series. Consider yourself warned!

Following Harrow's murder of Marc, Layla was forced to make a deal with Taweret to help free Khonshu from his tiny stone prison, and to do this, she had to become Taweret's avatar (which she insisted was temporary), giving her a superhero costume and powers of her own. Meanwhile, Harrow was able to free Amet, and start his plan to pre-judge the entire world of evil they might commit in the future. Thankfully, with Khonshu freed, Marc and Steven are both able to escape death and return to the land of the living, newly synchronized and able to use their Moon Knight powers together rather than against one another.

Things culminate into a major battle featuring the giant versions of both Amet and Khonshu duking it out while Layla and Marc come up with a plan to trap Amet in Harrow's human body, which would seal her in a mortal shell and allow her to be killed for good. They manage to pull this off, but at the last moment Marc decided he doesn't want to be a murderer and instead has Harrow committed to a mental hospital (named after comic book legend Bill Sienkiewicz).

Marc also, in no uncertain terms, rebuffs Khonshu's attempt to reclaim him as an avatar--or, at least, he tries to.

Unfortunately for both Marc and Harrow, it turns out there are parts of Marc's mind that even Marc and Steven are