Back-Up of Brave Rewards without Uphold or Gemini for reinstalling browser and OS

I need to reinstall my Brave browser (and OS), and I want to back up my Brave Rewards Wallet, which currently holds 28BAT. The easiest way would be creating an Uphold or Gemini account. But since January 2020, both wallets do not accept any new registrations from my country, which means I cant register nor verify any account. Unfortunately, Gemini does not support my country at all, and Uphold won´t work for a few months either.

Is there any other way to back up my Brave Reward without one of these? Is it possible to implement an independent wallet into the browser so that I can transfer the BAT to a wallet provider of my choice?

Thanks in advance