(Forgive the stupid AI answer, but does this help?):
2. Submitting an App Without a GitLab Account
To get an app listed on F-Droid, a metadata file must be added to the official fdroiddata repository. While the standard workflow involves opening a Merge Request on GitLab, you still do not strictly need a GitLab account: • Alternative Logins: The F-Droid GitLab instance allows you to sign in using your existing GitHub, Google, Bitbucket, or Salesforce accounts. • Community Submission: If you do not want to interact with GitLab at all, you can post a request on the F-Droid Forum, and community contributors can create and submit the metadata file on your behalf.
----- Apparently you don't need to actually create a gitlab account? Login with your github or whatever (I assume via oauth?)
The docs definitely don't look clear (on quick perusal), and maybe this info is outdated, but perhaps you can still push to gitlab without actually creating an account just need to make sure the metadata is correct?
Well that is another issue, It has been very difficult to follow their documentation. I read a bunch of pages that bounced me around links each containing a little information, but not in a manner I could turn into anything that I understood to be a clear path forward.
I asked on the #fdroid IRC channel without success. I only got as far as I did by asking an AI to decipher their documentation. I have posted on the forum, but it seems clear that this is a second class approach. It feels a little Kafkaesque to choose the non-GitLab path and have them recommend you use GitLab.
Sign in with an auth from another account is still creating an account, You may be able to use the other accounts to log in, but it still puts you through the sign up process asking a bunch of details.