Yes, you only have 1 ad in your region. I don’t know if you should use a VPN, never done so myself. Now if you don’t receive that 1 ad, follow this Brave Ads Windows 10 Troubleshooting to check if your system is set up correctly.
You can test the ads by: go to your rewards page > turn off ad rewards > wait a couple of seconds > turn them on again > don’t move your mouse for 20-25 seconds > move your mouse and check if an ad appears.