You can receive every time with a new address generated by HD Wallet. But transmission can only happen from an address which has positive balance. And after receiving the money, destination balance becomes positive, and you are bound to use that destination address as a source to transfer assets further.

Oh I wouldn't worry, they'll find a way. It's only 7 tx/sec lol, that's literally nothing. Not that hard to put 2 and 2 together.