Which is not correct. If F-Droid’s reproducible build system can get the same result as your own build, you can distribute your own, self-signed version through F-Droid.
To be fair, Moxie appears to have been right at the time of writing the linked comment according to the commit timestamp. Thanks to you (and the comment or above for the link) for pointing this out though. TIL. The documentation does say it is unlikely and other documentation has not been updated to point to this feature, such as the developer FAQ: https://f-droid.org/wiki/page/FAQ_-_App_Developers#Can_APKs_...