Can I optimize my Facebook advertising campaign for custom conversion events set up within ManyChat automation?

For example, if a custom conversion event within ManyChat automation is triggered when someone submits an email address, I would want to optimize my ads for this specific event - this way I’d get lower cost per lead and lead that matter.

This approach ensures that ads are shown to people who are more likely to convert, which is far more effective than a simple post engagement campaign optimized for comments, shares, or likes.

A backup plan would be to optimize for clicks through Messenger (instead of a flow being triggered when someone comments on the post), but it’s still less effective than directly optimizing for the custom event itself.

Is this doable?