It seems there is no standard proper way to store private keys.
I have been using AGE [0]
And I really don't like the idea of having the keys stored in the home directory in plain text.
There is also a risk of losing the keys if my laptop is damaged or gets stolen.
Is there a proper tool for storing encryption keys?
You can essentially encrypt all environment variables, not just SSH keys, by aliasing your terminal commands to the 1password CLI. I have a “secrets” repo where all dotenv files are checked in with values like “op://vault-name/secret-name/key-name” that get injected by the op cli.
[1] https://developer.1password.com/docs/ssh/agent/
[2] https://developer.1password.com/docs/cli/get-started/