R2 is set Public Bucket and used with workers/hono, CF-Cache-Status becomes BYPASS

I created R2 and created a public bucket with a custom domain managed by Cloudflare.
This R2 is supposed to host a static website.

At this point, when I access the website via the custom domain, I get
Cf-Cache-Status is MISS or HIT, confirming that the cache is working.

We deployed the workers created by hono and configured workers routes for this custom domain.
Within workers, we reverse-proxy by issuing a sub-request as shown below.

return fetch(context.req.raw)

When the website is accessed via the custom domain again,
Cf-Cache-Status was BYPASS and the cache was not working.

What configuration should I use to ensure effective use of the cache?