Hello there,
Thank you for reaching out to us.
In the API's perspective on creating location extensions, you can simply follow these existing API guides (using AdWords API | using Google Ads API). As for your concern if a dummy category or imprecise category could impact the ad/keyword ranking, I'm afraid that performance guidance is already out of our team's expertise. You can reach out to the Product Team (via this link) instead as they're much capable of providing more details as to how this would impact your ads.
Regards,
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| Mark Kevin Albios |
| Google Ads API Team |
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