The answers are there, you just don't want to admit they are right answers...

Well, this problem does not exist. The socket is created before bind is started, so a bind client will never notice that bind is in fact not yet started, or might still be in the process of starting up: because it can connect the socket just fine.

So, the whole idea of "application bombs out if bind is not yet started" is bogus. Doesn't exist in the systemd scheme.