SSH: The agent has no identities. (Searched the community first.)

Thanks, @MartonS1P , floris_1P , for your answer.
Yesterday, I managed to solve the issue by doing a clean install of 1P, as 1Password_rCURRENT.log wasn't verbose enough either for me to keep investigating.

After that, ssh-add -l started working smoothly:

ssh-add -l
256 SHA256:zojQYofphA1Wfx*****d8qb96m5*****wInWxxS4 v-proxy_Ed25519 (ED25519)
3072 SHA256:us47I3bBvYXr3*****MNB4jr9gcvPp/U*****vk ftpjcmgt02_Ed25519 (RSA)
4096 SHA256:aVPGbgByminaTsO*****b538Ivmn1CzNnRDsZrgj3g GitHub SSH Auth Key (RSA)
256 SHA256:eMFn+ah2/Xd/cAM5s4mtZJMVVjPgUT*****P7kJTD8 GitHub SSH Signing Key (ED25519)
3072 SHA256:qn4luzQ53LP*****RJQFbCs1/oD2A53+****+up+6c Clave SSH (RSA)
3072 SHA256:oaqyyLdfKysKtv0aZR******Hq7tMbQ1tHZOWok1SE id_rsa_rpi2 (RSA)

floris_1P , it happened to me both on Docker and ordinary terminal, and yes, they are placed on my Personal Vault.
What I've noticed though is that setting the symlink on the .ssh/config does not work, and have to use the absolute path to the socket:

Host *
IdentityAgent "~/Library/Group Containers/2BUA8C4S2C.com.1password/t/agent.sock"
#IdentityAgent ~/.1password/agent.sock # <--- this does not work, no matter if single-or-double-quoted or not
[... other ssh config ...]

Maybe that's normal for .ssh/config syntax, I am not that expert on ssh.