Please our article on reporting on results from Facebook Ads with SyncWith

SyncWith does not support reporting on custom metrics that you've created in Facebook Ads.

However, you can create custom fields (using formulas) when reporting on Facebook Ads using SyncWith for Google Sheets or using SyncWith's Facebook Ads connector for Looker Studio.

You can track actions that your users are taking to Facebook Ads as events, Facebook supports both Standard events and Custom events.

SyncWith doesn't support reporting on events from Facebook, this include standard events and custom events.

However SyncWith has full support for reporting on Custom conversions, and its possible for you to create a custom conversion at Facebook that is triggered by standard or custom events, and that way you could report on that easily using SyncWith.