[nickjj]

This is what I do too, I've written about it in detail at: https://nickjanetakis.com/blog/using-a-custom-ssh-key-to-acc...

You can also set that in your `.git/config` file on a per repo basis. Additionally you can set `GIT_SSH_COMMAND="ssh -i /tmp/custom_key_ed25519 -o IdentitiesOnly=yes" git pull` to override whatever is in your global or repo config for 1 off pulls / clones as a different user.

[nine_k]

This is indispensable when you have to clone a repo, so no config settings based on being inside a repo do not apply.