IndexedDB is slow as hell. Chrome implemented IndexedDB on top of LevelDB and Firefox on top of SQLite. Almost all fast-enough web clients cache events in JS memory instead of query from IndexedDB on every read.

This is also why I intentionally do not implement storage layer for nostr.ts.

Browser is not designed for local-first, client driven applications.

If you implement NostrDB on top of IndexedDB, you effectively implemented it on top of SQLite/LevelDB which is exactly what you planned to avoid at the first place.