@ibnesadik as it says, Bangladesh is currently not supported. The list of countries eligible to link and earn can be seen a thttps://support.brave.com/hc/en-us/articles/6539887971469
All you can do is wait for more options to be available in your region. One such thing in the works is on chain payment, but no idea when it will be available. You can read through a post on it and read associated links for more info at PSA: Current and upcoming changes to Rewards and Creators