SharePoint 2013/2016/2019: How to replace expired WorkFlow Manager Certificates

I got the exact problem. I added my account (logged into the server) to the managed user list per this link https://stackoverflow.com/questions/30023884/cannot-join-workflow-farm-add-wfhost . The issue was resolved, then I used ps scripts I saved from earlier step to add host to wf farm.

# Get SB Client Configuration

$SBClientConfiguration = Get-SBClientConfiguration -Namespaces 'WorkflowDefaultNamespace' -Verbose;

# Add WF Host

$WFRunAsPassword = ConvertTo-SecureString -AsPlainText  -Force  -String 'workflow acct pwd' -Verbose;

$WFCertAutoGenerationKey = ConvertTo-SecureString -AsPlainText  -Force  -String 'cert gen key - passphrase' -Verbose;

Add-WFHost -WFFarmDBConnectionString 'Data Source=****;Initial Catalog=******;Integrated Security=True;Encrypt=False' -RunAsPassword $WFRunAsPassword -EnableFirewallRules $true -SBClientConfiguration $SBClientConfiguration -EnableHttpPort  -CertificateAutoGenerationKey $WFCertAutoGenerationKey -Verbose;