In fact, without taxes, theft doesn't really have a meaning.
The thing is, property is not an objective reality. There is no empirical test you can perform that will determine if an object belongs to someone, and to who. Property is a social convention.
You only own something to the extent that you control it. You have it, and someone else doesn't. But someone bigger and stronger than you can take your stuff, and there's nothing you can do about it. Even if you're the biggest strongest person there is, a group of people can overpower you.
One of government's functions is to protect property rights. If you own something, someone bigger than you isn't allowed to just take it from you. And if they try, well, government is the biggest one around. And government needs taxes to operate. You need funds to pay for the police who will stop people from stealing.
Without taxes, the enforcement of property rights collapses, and property ceases to exist. And you can't have theft without property.
Beyond even that, taxes pay for roads and other infrastructure, which you're in debt to, even if you don't use it directly. Even if you don't own a car, you still get a benefit out of roads, because grocery stores you shop at are supplied via roads. Even if you have never needed medical care in your life, public medical care benefits you by herd immunity. The list goes on.
Wanting to get these benefits without paying for them is closer to stealing than taxes are.