Multiple git repositories with multiple ssh keys

Generating a new SSH key:

user_name@localhost:~$ ssh-keygen -t ed25519 -C "hello@example.com"
Generating public/private ed25519 key pair.
Enter file in which to save the key (/home/user_name/.ssh/id_ed25519):/home/user_name/.ssh/id_ed25519_repo_name

Add it to repository deploy key.

vim ~/.ssh/config:

Host github.com-repo-name
        Hostname ssh.github.com
        IdentityFile=/home/user_name/.ssh/id_ed25519_repo_name
        Port 443
        User git

vim .git/config:

[core]
        repositoryformatversion = 0
        filemode = true
        bare = false
        logallrefupdates = true
[remote "origin"]
        url = git@github.com-repo-name:github_user_name/repo_name.git
        fetch = +refs/heads/*:refs/remotes/origin/*
[branch "main"]
        remote = origin
        merge = refs/heads/main