Cloudflare's Durable Objects puts your Worker and SQLite DB on the same physical server (and lets you easily spawn millions of these pairs around the world).

D1 is a simplified wrapper around DO, but D1 does not put your DB on the same machine. You need to use DO directly to get local DBs.

https://developers.cloudflare.com/durable-objects/

(I am the lead engineer for Cloudflare Workers.)