Privacy. How to prevent transaction recipient tracing prior transactions of mine I am thinking of sending some BTC to a new BTC address, but do not have complete trust in that new one. 

I'm sending to someone else, but want to be sure that if I do, they can't access other people I have used the same BTC wallet to send BTC
You might want to consider finding a reliable Bitcoin Tumbler (Bitcoin Mixer).

But be aware that you are placing trust in a third party, especially for custodial mixers. Some people have lost money to fraudulent mixers. I would do my research into a company very carefully before risking using them.

Some wallets have mixing capabilities built in to them. These may be a better option.

One example of an article on the subject is How to Mix Your Bitcoins Using Coinjoin for Greater Privacy -- but I can't vouch for the correctness of this article. I suggest taking the time to do your own research.