I have one remaining worry about Brave: If I choose to auto-contribute to sites, would it be possible to deanonymize me and derive what I look at from the BAT blockchain? E.g. if someone knows some of the sites I look at can they find out the rest?
These contributions aren't made on the public blockchain, so there is no way (not even for Brave) to know which site(s) you're supporting. Note also that (by default) the Brave Rewards wallet has no requirement for KYC. As such, there is no information about [you] connected to these transactions.