@Mike Apologies for the delayed response, As I understand you want to get forgot my PIN option on the logon screen to be functional (after deploying WHFB).
Wanted to check if you have reviewed this doc - https://learn.microsoft.com/en-us/windows/security/identity-protection/hello-for-business/pin-reset?tabs=intune which talks about the configuration of Microsoft PIN reset service enables your users to recover a forgotten Windows Hello for Business PIN.
Let me know if you have any further questions, feel free to post back.
Please remember to "Accept Answer" if answer helped, so that others in the community facing similar issues can easily find the solution.