@alpacahino,
Copying over your user data folder is your best option here.
C:\Users\[your user name]\AppData\Local\BraveSoftware\Brave-Browser\
This should carry over estimated Rewards. Note that if you continue using the browser on your old machine as well as your new one, you may run into unexpected behavior. You should only use this to restore into your new machine, and retire your old machine once you restore into your new machine.
Not entirely sure i understand the question. Are you asking if there is any way to transfer estimated earnings if you don’t have access to your old PC? If so, the answer is no unfortunately.