This means that through transactions they can reach a person in the form of tracking? He thought that he was very anonymous and that was what really worried the federal agencies, legal entities, not being able to find who did the ''theft''
By he, do you mean the quoted user above? Then yes. He mentioned using different seed/wallet to make transactions and a mixer to bridge one to the other. Personally, I don't think that will guarantee that any chain analysis company won't be able to break down the link, but it should take some time unless they use a terrible mixer. You should not expect privacy if you use any KYC-ed platform to begin with.