In the Custom Segment form (Create Audiences › Google), below the Sites field, the Suggest competitors button uses AI with web search. It works from the searches that convert in your account (or the ones in the Searches field) and the region of your campaigns. It uses AI credits (about 2 per use). Each site comes with a reason (for example, "appears for sp facial harmonization" or "advertises on Google: 24 ads"). Select the ones you want and click Add selected, which adds them without deleting what is already in the field. Your own site, marketplaces, directories, social networks and portals are left out.

Auction information (who competes with you in the auction): Google doesn't release this report through the API, so it can't be pulled automatically. Instead, download the report in Google Ads (Campaigns › Insights and reports › Auction information, as CSV or Excel) and use the Import Auction Information button in the same form. Ads Editor shows each domain's impression share and overlap.