Updating Data Values After Custom Validation Code in wpcf7_before_send_mail()

I’m using the wpcf7_before_send_mail() function to run some validation checks on the data using a third-party lookup service’s API for spam prevention purposes.

The issue I’m running into is that there’s custom (hidden) fields that I need passed along, so that the API responses are visible in the email, Flamingo & accessible as a field value that another plugin can use to send off to the client’s CRM.

In earlier versions of the plugin (before an update in the 5.x series IIRC that changed things), based on code examples I found online there used to be a set_posted_data() function that could be used for this, but now that doesn’t exist anymore.

How can I update those fields now using the latest version of the plugin? I had saw a response elsewhere on this support form that linked to a filter, but I don’t think that would work in my situation as the API response is done inside wpcf7_before_send_mail() and wouldn’t be accessible in the filter?