I think all taxes could switch to a fee-for-use model, like car washes, or a subscription model, like insurance, that isn’t very intrusive.
At a car wash, you aren’t paying a subscription for the place to stay open. You pay only when you use the car wash to clean your car. A similar model can be used for government services that are best fit for this. Take roads for example. Many roads are already paid for with a fee-for-use model. Fuel taxes pay for roads, if you drive then your car consumes fuel and so you pay for roads when you refill your car with fuel. A more direct fee-for-use example would be a toll road.
With insurance, you tell your insurance company what kind of car you drive or where your house is, and they figure out approximately what the items are worth so they can charge you a reasonable premium to protect those assets. Then you pay a monthly premium, and if anything happens to the assets that are covered by the policy, you are compensated with a repair or replacement.
In neither case are individuals required to divulge the details of their financial transactions. Since the services the government offers have nothing to do with the specifics of our financial transactions, there’s no practical need for the kind of invasive financial surveillance they use nowadays for tax enforcement.
An additional benefit of the above models is simplicity. Rather than needing an army of accountants to tell me what I owe, I just pay-as-I-go in the fee-for-service model, as I do when I get a car wash, or pay a monthly invoice in the subscription model, as I do for my insurance.
This maps closely to the “territorial-based taxation” model you describe in your note @GustavMarwin.