No matter what kind of technology you develop you can't circumvent events that trigger taxes. It doesn't even make sense to say that any technology product helps to prevent taxes in a legal way. Whenever you purchase a sell a crypto you have to pay taxes no matter what in most countries of the world. How are you allegedly going to prevent taxation in a legal way?
We are not preventing taxes, but we want to minimize them. Also at the moment, you pay taxes only when you cash out, but not if you pay directly in crypto.
That is not true for most parts in the world. In almost every country paying with crypto is a taxable event (capital gains). And changing BTC into ETH is also a taxable event almost anywhere in the world. You should get familiar with that stuff before you build blockchain solutions