spent HOURS figuring this out. turns out you cant make fetch request from worker to another e.g https://website.chiubaca.workers.dev cant make fetch call to https://backend.chiubaca.workers.dev. it will fail with error code: 1042, apprently for security reasons. The workaround is to bind a custom domain to a worker, which puts it into a different zone.
Advanced workaround is to make use of service-to-service bindings, which can place your workers so they have direct communication with each other have have zero latency.