This article's method is bad, basically the same as systemd-creds (not itself bad, just extremely compatible), take a look at tpm-ssh-agent or gnupg for how to

This article's method is bad, basically the same as systemd-creds (not itself bad, just extremely compatible), take a look at tpm-ssh-agent or gnupg for how to do that part the right way (the party they don't do right is bind/sign to pcrs, which is just low hanging fruit in today's day and age...)