So while yes, a dedicated app for SR would probably be "better", i'd then have to make tightly coupled user experiences to sync data back and forth between my knowledge base and my knowledge retention app.

To me they're two sides of the same coin. With that said i've long wanted to make my own app here for this stuff, but Obsidian seems very customizable, so i'm thinking i'll just try to make an extension which embeds the necessary metadata into the markdown files themselves.