Is forking a coin like monero or bytecoin the only way to create a privacy coin? or is there some other blockchain? like erc-20 but for privacy coins
You can make even your bitcoin and other coins private as privacy is a feature that can be added to any blockchain. There are so called mixers that mix up all coins and it is not understandable then who is the owner of those coins.The most popular privacy platforms are Tornado.Cash, Coinjoin. They break the correspondence of addresses at the entrance and exit of funds from the contract, and due to this, it is possible to achieve privacy.