‘Midnight Mass’ Ending Explained by Creator Mike Flanagan

"reminds me of Darth Vader escaping at the end of Star Wars" - hey, spoiler alert, thanks for ruining it for me!

Next you'll be telling me some shit like Darth Vader is Luke's father...

The Angel is a metaphor for religious fanaticism. And he wasn't intended to imply that the vampire had died.

A lot of people presumed that Leeza's inability to feel her legs meant that the angel had died, trying to make it over the ocean. If it died, the healing abilities from its blood would cease to function, or at least, that's what people were theorizing. It wasn't established as part of the show's mythology that killing the angel would revert all of the changes.

Flanagan is clarifying that though it makes sense that way, that wasn't his intention at all. (To keep this simple,) the ending had two points, one literal and one figurative:

Literal
-Leeza lost her mobility because her blood started to tip back in her favor

Figurative
-The fate of the angel was intended to be open-ended because the threat of religious fanatism is always a possibility. You can never get rid of it entirely.