To keep your privacy, never use and mix addresses from previous business
Which is why I recommend using Electrum, where you have several bitcoin addresses you can use for different transactions. It’s not easy to maintain privacy in today’s world, I think it’s also noteworthy to add that using block explorers can reduce your privacy. When you repeatedly search a wallet address on an explorer, they can easily figure that the addresses belong to you. Make sure to use TOR when using block explorers.
Don’t mix KYCed and private coins
You are going to mix KYCed coins, possible compromising your privacy. Every time, your private coins and your KYCed coins are mixed, more can be found out what you have done before for your private coins as such coins are now also tied to your real information. Always be careful when mixing your private and your KYCed coins.
I’m confused here. When you say private coins, do you mean coins like monero and dash? Or simply coins that haven’t been linked to your identity?