I encountered a problem because I have multiple keys, and I have to name each one.

Check this Azure doc resource: https://learn.microsoft.com/en-us/azure/devops/repos/git/use-ssh-keys-to-authenticate?view=azure-devops#q-how-can-i-use-a-nondefault-key-location-that-is-not-sshid_rsa-and-sshid_rsapub