In practice, I don’t plan on adding an entire proprietary layer - that is just way too much work, and it defeats the purpose. If the open source code has bad performance, why would someone even bother with a hosted version? Like, I want people to be so impressed by the open source code that they’d trust a cloud version to be even better. Clickhouse and duckdb do this very well.
The main difference I expect with a hosted solution are things like multiple tenants or billing integrations. These aren’t core to the product and only necessary when you need to host someone else’s data.