Hello @LeaLaw2020! 👋
Unlocking 1Password using your Apple Watch requires a Mac with a Secure Enclave because the Secure Enclave offers additional security beyond what the macOS Keychain provides. After you set up 1Password to unlock using your Apple Watch, 1Password saves an encrypted secret that represents your account password to disk and the key to decrypt it in the Secure Enclave. Only 1Password can ask to use the key and only the Secure Enclave can decrypt the secret.
The following Macs include a Secure Enclave:
- iMac Pro (2017 and newer)
- iMac (27-inch 2020 and newer)
- MacBook Pro with Touch Bar (2016 and newer)
- MacBook Pro (2018 and newer)
- MacBook Air (2018 and newer)
- Mac mini (2018 and newer)
- Mac Pro (2019 and newer)
It doesn't look like the 4K 2017 Mac is included so you're correct that you won't be able to unlock 1Password using your Apple Watch.
I don't recommend using any third-party apps to unlock 1Password since you would need to give those third-party apps your account password. Your account password should be something that you memorize and don't write down or store anywhere. I know that this probably isn't the news that you were hoping to hear but I hope that this helps to explain things.
Let me know if you have any questions. 🙂