Create a new repository, or reuse an existing one.
Generate a new SSH key:
ssh-keygen -t ed25519 -C "your_email@example.com"
Since OpenSSH version 8.2 using FIDO2 security keys for SSH is recommed.
https://github.blog/2021-05-10-security-keys-supported-ssh-git-operations/
OnlyKey & Nitrokey 3 support ed25519 keys with OpenSSH. Only a YubiKey with firmware 5.2.3 or higher supports the ed25519 curve!