Closing the PR without providing feedback beyond "needs further discussion" does not engender said further discussion.
and there is open issue for that discussion https://codeberg.org/forgejo/forgejo/issues/8634
> In the v12 release of Forgejo (fixed in v12.0.1) there have been breaking changes that impact third-party authentication sources that use Forgejo as a provider. If you have been affected, please help us assessing the impact ...
There also was feedback saying approximately that they've been burned by security changes in the recent past and don't want to run into similar issues without due consideration.