I'm surprised no one has mentioned this before and why Stake continues to think it's acceptable behavior.
Stake subtracted $3.09 from my withdraw
https://ibb.co/mRc56hyCost of the transaction on the blockchain was only $1.69
https://ibb.co/4m3gg6LSo my question remains what did Stake do with the remaining $1.40

It is a big amount to go missing especially when some Sportsbooks don't charge anything.
Welcome to centralization, this is not a thing we've never seen before so am honestly surprised you are complaining about, this behavior isn't of stakes alone, all centralized exchanges have a flat fee which they charge for withdrawals and the worst the state of the network around your time of withdrawal, the higher the fees, and please note that the fee you pay will always be higher than what the network will take to confirm the transaction, this is one of the many cons of centralization.
So, if stakes charged you $3 for a withdrawal which the blockchain network took only $1 to confirm the transaction, then consider the remaining $2 as money which stakes uses to maintain their site, pay workers salaries, plus other miscallicious expenses.