I am in the same situation. After a couple of meetings with an official Google Tag Manager technician, he told me that we have detected that the Google Listing and Ads plugin generates a very simple datalayer, which, together with the GTM4WP datalayer, duplicates events. The problem is that the GTM4WP datalayer is considered by Google technicians to be official and more complete. The Google Listing and Ads datalayer is NOT.
The Google technician suggested that I contact you, the Google Listing and Ads support team, to request the functionality to enable or disable the datalayer generated by your app, so that we can choose whether to use it or not. Could you please add this functionality to enable or disable the datalayer?