Many years ago I tried Tabbles (https://tabbles.net/en/), apparently it still exists, but it just didn't work out so well. The main concern is compatibility. I tag up my stuff meticulously and then the project is killed and I'm left with wasted effort.

I think the idea will go away, similar to how ontologies and Semantic Web, manual knowledge graphs etc gave way to processing unstructured data with LLMs. Instead of tags, we should have source/creation-context-based metadata and embeddings computed with language models. Then you can do natural fuzzy search.