On Ubuntu 21.10 my Emacs running keychain-refresh-environment doesn't interact well with the gnome-keyring-daemon so it starts a fresh agent and doesn't get the right SSH_AGENT_SOCK and SSH_AUTH_SOCK.
This very fragile little bit of emacs code looks for a socket in the place my gnome-keyring-daemon stores it (by default /run/user/<uid>/keyring/.ssh) and if it exists then emacs will call pgrep to try and get the PID of the agent associated with it.
All you really need us something like this:
(use-package get-ssh-agent-gnome-keyring-daemon
:config
(get-ssh-agent-gnome-keyring-daemon))
If it succeeds then it will return t, but also set the variable get-ssh-agent-gnome-keyring-daemon to t. If it fails it will return nil and ensure that get-ssh-agent-gnome-keyring-daemon is also nil, which is also its default value.
If you already use the normally excellent keychain-environment in some places but want to make your config portable then you can try something like this:
(use-package get-ssh-agent-gnome-keyring-daemon
:config
(get-ssh-agent-gnome-keyring-daemon))
(use-package keychain-environment
:ensure t
:config
(if (not get-ssh-agent-gnome-keyring-daemon)
(keychain-refresh-environment)))
So if there is already a running gnome-keyring-daemon it doesn't try keychain-refresh-environment (which will probably start another ssh-agent)
The function accepts two named arguments :socket and :pgrep-template which can be used to override the default methods used in the function. The :socket has any single quotes removed from it. The :pgrep-template should be a format string with a single %s escape in it, which is where your socket path will be put.
You can use one, or both, of these as you see fit.
(get-ssh-agent-gnome-keyring-daemon
:socket "/path/to/your/socket/.ssh"
:pgrep-template "your-pgrep 'ssh-agent %s'")
Just keep in mind this is going to be put into a shell command and I can't guarentee this is totally secure. You have been warned.