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.