Hi
Please, first check here
if Uphold or Gemini Custodial wallets are supported in your country.
Also check If Brave is supported in your region here https://brave.com/transparency/
and also the Brave Ads Catalog for your region here https://sampson.codes/brave/ads/my_region/
Finally, I hope the following link will answer your questions about Brave ads FAQ: Why am I not seeing Brave Ads?