transactions are public but if no one knows that a public key is yours it's difficult to trace. and like you said, there's tools to anonymize your bitcoin transactions completely
Tumbling is supposed to make tracking non-trivial. Anyways you can always convent to another coin, especially one with more anonymity, and then back to Bitcoin.
don't keep your bitcoin in exchanges. it defeats three of the main appeals of bitcoin: autonomy, trustlessness, anonymity