Age only covers encryption. It does not cover signing, ssh, web of trust, hierarchical keys, key discovery, etc. It is in no way a replacement for a modern PGP keychain.
Ignore GnuPG which is a shit show stuck in the 90s. PGP != GPG
For a modern long lived personal PGP keychain use Keyfork on AirgapOS which gives you a secure 24 word mnemonic backup, optional split backup across redundant smartcards, and a separation of a CA key and daily driver subkeys on smartcards all done correctly so you do not have to think about it. I would suggest a Nitrokey Pro due to open source rust firmware, though Yubikeys are supported.
From there you can use your smartcard for ssh, password management, git commit signing, etc. and make your key easy to discover without impersonation using keyoxide to have all your services, domains, etc attest to your key, as well as any humans who vouch for you.
A proper PGP keychain is a long lived digital passport first, that has encryption and authentication subkeys.
https://git.distrust.co/public/keyfork
https://git.distrust.co/public/airgap
Ignore GnuPG which is a shit show stuck in the 90s. PGP != GPG
For a modern long lived personal PGP keychain use Keyfork on AirgapOS which gives you a secure 24 word mnemonic backup, optional split backup across redundant smartcards, and a separation of a CA key and daily driver subkeys on smartcards all done correctly so you do not have to think about it. I would suggest a Nitrokey Pro due to open source rust firmware, though Yubikeys are supported.
From there you can use your smartcard for ssh, password management, git commit signing, etc. and make your key easy to discover without impersonation using keyoxide to have all your services, domains, etc attest to your key, as well as any humans who vouch for you.
A proper PGP keychain is a long lived digital passport first, that has encryption and authentication subkeys.
https://git.distrust.co/public/keyfork
https://git.distrust.co/public/airgap