Access Worker url as "directory" from Pages app

Following the Plausible guide on how to proxy the event route to be within the app (https://plausible.io/docs/proxy/guides/cloudflare#step-6-optional-run-proxy-as-a-subdirectory), I then tried to access my site script: https://site.tld/_pl/js/script.js but I get a 404, which makes me think that the app (SvelteKit for the context) takes over the worker by showing an internal error and blocks accessing the Cloudflare Worker. The SvelteKit site is also hosted on Cloudflare Pages. Do you know how I can fix this? Is it related to my app routes or Cloudflare here?

Proxying Plausible through Cloudflare | Plausible docs

You can use Cloudflare Workers to proxy your Plausible Analytics requests. Cloudflare Workers offers free service for up to 100,000 requests per day.