Nobody of my friends knows my password and don't know that I play on stake.com
if account would be hacked how it's possible that it happened in short margin of time between my 2 bets.

In my opinion it's just an error at stake.com.

What would be a benefit for somebody who could hack my account to clean it out instead of withdrawal all fund to his TRX address?

I wonder why stake.com does not want to check logs?