This is a funny thread to me because my frustration is at the intersection of your comments: I keep wanting sqlite for writes (and lookups) and duckdb for reads. Are you aware of anything that works like this?
I think you could build an ETL-ish workflow where you use SQLite for OLTP and DuckDB for OLAP, but I suppose it's very workload dependent, there are several tradeoffs here.
DuckDB can read/write SQLite files via extension. So you can do that now with DuckDB as is.
https://duckdb.org/docs/stable/core_extensions/sqlite