The most anonymous form of bitcoin is to set a full desktop blockchain wallet. Then find a bitcoin atm to fund it. Any other way, means you will be using a third party to at least get funds into your account or hold your account for you. The reality is unless you are running the full bitcoin blockchain wallet or the new abbreviated blockchain wallet, from your computer, some one will have at least some knowledge of your bitcoin usage. Technically most third parties holding your wallet, say they do not know what keys you are using to receive or send funds so that should be anonymous, but when you log in or out, is probably known to them. It should be noted that the bitcoin atm's have cameras in them and technically they are suppose to get a picture id from you. The one closes to me is 60 miles away, I've been there a few times, before switching to circle because it is cheaper to deposit with circle, never had to show id.
Bitcoin can be very easy to use relative speaking once you get money into your wallet. The trouble for most people is getting money into your wallet. For some as anonymous as possible. At one point I was hoping bitcoin would really catch on, now I want it to stay among the more tech savvy. Because once keeping peoples wallets become a big enough business, the big financials will find their way into the market and find a way to drive up processing costs. And of course force regulations to benefit them more than the user.