I had being using krypton, with the private key being on my iPhone, and am now using secretive. Never had much of an issue with not having access to my private key. We made rolling out public keys to the servers very easy by using the gitlab key file. So when I get a new Macbook I'd just need to create a new key and upload it to gitlab. We have multiple devops that can run the playbook to roll it out to the servers. And if they have a new Macbook I roll it out for them. And we don't have that many Macbook upgrades anyway.