> What I’ve realized recently while learning Rust (no Anki involved) is that, for me at least, new information needs something to “cling on” to. I wonder if this Spacing Effect is another facet of the same idea.

I think the concept you are looking for is "schema."

In psychology and cognitive science, a schema (plural schemata or schemas) describes a pattern of thought or behavior that organizes categories of information and the relationships among them. It can also be described as a mental structure of preconceived ideas, a framework representing some aspect of the world, or a system of organizing and perceiving new information. Schemata influence attention and the absorption of new knowledge: people are more likely to notice things that fit into their schema, while re-interpreting contradictions to the schema as exceptions or distorting them to fit. Schemata have a tendency to remain unchanged, even in the face of contradictory information. Schemata can help in understanding the world and the rapidly changing environment. People can organize new perceptions into schemata quickly as most situations do not require complex thought when using schema, since automatic thought is all that is required.

https://en.wikipedia.org/wiki/Schema_(psychology)

See also "Memory Palace" or "Method of loci."

It turns out the mental athletes were purposefully converting the information they were memorizing into images, and then placing these images into a mentally constructed “palace” — thus the involvement of visual memory and spatial navigation.

https://fs.blog/the-memory-palace/

Edit: I think schema is to spaced repetition what access is to storage. They are at their best when put together.