Unless there is a way to add a Secure Enclave (hardware) to such a machine, I don't believe that'll be possible; sorry.
Thanks, but the question is if Apple can enable the Apple Watch for security on these iMacs without Secure Enclave (hardware) then why can't 1PW use the same logic (API?) for security? Seems to me that if I can unlock Apple iCloud passwords then shouldn't 1PW have sufficient security?
I apologize but we require the Secure Enclave for this feature as that is the only way that meets our security requirements. I wouldn't be in a position to comment on what other apps/services do/allow.