I wrote a macOS app that supports using Vault Transit Engine keys with OpenSSH, as well as GnuPG and PKCS#11. (OpenSSH is supported via both the agent protocol and PKCS#11.) You can even use an Apple T2 (Secure Enclave) key for peer mTLS authentication to the Vault server. https://www.keymux.com/

Using this teams can share an SSH key without exposing the key; nor do you need to configure certificate PKI, use jump hosts, or otherwise change your existing software or workflows.