There's a popular sentiment online that Ranni's ending removes the influence of the Outer Gods upon the Lands Between. This is something I've seen pop up a lot in the many discussions regarding her ending, but I was unable to find in-game if this is something her ending actually does.
As I understand it, Ranni removes the Elden Ring by taking it with her as she embarks on her Thousand Year Journey into the stars. By removing herself, a God at this point, and the Elden Ring, she thereby removes the mechanism that defines and enforces a specific, divine framework of reality. It restores the proper cycle of the world by uprooting the tree (Golden Order) and its rotten roots (Elden Ring), so new beliefs can develop, but without the guarantees once by provided by the Elden Ring and its God.
In that absence, individuals are no longer guided by an inherited framework that tells them what is what. Presumably new ideas and beliefs can grow as people pursue whatever they wish with a greater sense of autonomy.
But here's the thing, I only ever interpreted this as meaning the only god that gets removed is herself. Gods as in the type we saw with Marika and Miquella, not capital G gods like the Outer Gods. Aside from not really being mentioned by Ranni, Outer Gods themselves seem to have been around for a VERY long time, predating even Marika's age. So I don't see how Ranni removing herself, or her Elden Ring, would seem to impact their ability to influence the Lands Between?
The only interpretation I could come to is that it would remove their ability to interface with the Elden Ring? But they'd still be around influencing stuff on the planet, and really only one Outer God (Frenzy Flame) seems to be interested in doing that - so I feel that point is kinda moot? It also just seems contradictory to what her ending wants to achieve, which is the exact opposite of what we saw with Marika using the Elden Ring to impose what she wants over the world. Cutting off the influence of the Outer Gods, good or bad, runs pretty counter then to allowing people to pursue their own paths on their own terms.
Curiously, what Marika did in her age seems to be more inline with the idea of using the Elden Ring to restrict the influence of the Outer Gods. As she basically monopolized death to mess with the Outer Gods of Death and Rot, or confine their followers as seen with the Fell God and the Frenzied Flame. But of course even that didn't prevent their existence and continued meddling. I'm also not saying what Marika did was good, it wasn't, and the consequences of those actions make me question if restraining the Outer Gods is a good idea at all as you're basically meddling quite heavily with the natural world.
But yeah, I probably missed something since this idea seems to be so popular, and honestly it is a reassuring thought to know her ending would prevent shabriri from putting the Lands Between in a microwave.