Update Jan 25, 2022: Thank you everybody for your patience. We are working with the Gemini team to get everything back up and running. We currently expect Gemini user wallets in Brave Rewards to be back online around Feb 2-3, 2022 (next week).
Overall updates have been getting shared more readily on Reddit, so you can keep track at https://www.reddit.com/r/BATProject/comments/s6fiy6/verifying_brave_rewards_with_gemini_is/