TYPO3 Core

Thanks for the report Christopher.

Just as a remark - with TYPO3 v12.1 this behaviour has changed.
Auto-created redirects are stored on the corresponding "Site Root"
with #99044 [1] and a upgrade wizard is provided to migrate the existing
redirects.

This has been previously changed to be on the pages as a feature for an
agency needing this #91776 [2] - but it played out to provide headache,
as you described. Along with other things changed in v12 (introducing
a generic overhaul regarding the auto-redirect creation along with a
couple of events) the moving to the site-root was a preparation patch.

I don't think this will make it back to v11 in any way, as it would kind
of a behaviour change for a long standing LTS version.

For composer based installations, you could try to manually backport the
TYPO3 v12.1 change [3] to TYPO3 v11 and using a composer patch. But this
will not be provided officially

Additionally, you could try to extract it to a extension and replace the
core redirect service to override the behaviour and doing the same.

[1] https://docs.typo3.org/c/typo3/cms-core/main/en-us/Changelog/12.1/Important-99044-EnsureAuto-createdRedirectAreStoredOnConnectedSiteRoot.html
[2] https://forge.typo3.org/issues/91776
[3] https://review.typo3.org/c/Packages/TYPO3.CMS/+/76521

This just as a first remark - I will have a relook if we could find
another solution for v11 but this can take some time as I have pressure
on other tasks currently.

When its fixed in v12, then its fine for me to use composer patches. Thank you!