If you're using Azure DevOps Git SSH you have to use an RSA key. This is because Azure DevOps doesn't support the newer ed25519 keys (at time of writing). However newer versions of OpenSSH prefer ed25519 keys over RSA keys.
You have to force OpenSSH to use RSA keys for Azure DevOps Git SSH. You can do this by setting
PubkeyAcceptedKeyTypes in your
Then you can connect to azure with
git clone git@myazuredevops:myorg/myrepo.git. Just replace ssh.dev.azure.com with