Confidental Transactions and Coinjoin could help you make your Bitcoins less trackable, but it come down to end user how much info he gives.

Seriously, the address in the OP is so much reused (over 1 M moved through the adress with final balance just few thousands), which mean owner of this address dont care about privacy at all - Confidental Transactions or Coinjoin would not help him to get more privacy if he keep reusing the same address again and again !