Issue #782 describes an issue with XDebug when FrankenPHP's worker mode is enabled. You're likely experiencing a similar problem.

I also recommend checking out the docs/xdebug.md for more information on configuring XDebug for VS Code.

See https://frankenphp.dev/docs/worker/

ok boot time, how enabled for prod and not in dev?

This discussion was already at #782. See #782 (comment).

Strange, watch is enabled in compose.override.yaml but it's for prod?

inDockerFile

FROM frankenphp_base AS frankenphp_dev
ENV APP_ENV=dev
ENV XDEBUG_MODE=off
ENV FRANKENPHP_WORKER_CONFIG=watch

Which value for prod?

watch is a FrankenPHP option for automatically restarting when changes are detected in project files. See https://frankenphp.dev/docs/config/#watching-for-file-changes.
This option is enabled only for the dev environment because file changes are only expected for this environment. In prod, files shouldn't change, and this option is not needed for prod. Therefore, this option is enabled only for dev.

The FRANKENPHP_WORKER_CONFIG environment variable was added to the Dockerfile for the frankenphp_dev target in #765. This PR enabled worker mode for dev. Before this PR, worker mode was enabled only for prod.

You can revert #770 and #765 for your project to restore the previous behavior (so that worker mode only works for production). After revert and rebuilding the image, XDebug should start working. See #782 (comment).