Just links at the moment:
I'll follow with more notes...
I'm getting there. For me an important step was to remove the use-ssh-agent from /etc/X11/Xsession.options. I had to reboot for this to take effect.
Now I'm getting this:
Message: couldn't set environment variable in session: The name org.gnome.SessionManager was not provided by any .service files
If I set the environment variable manually, its all good.
Will this help?