I mean, there are countries where tourists don’t have to pay tax on top of items (meaning they pay for it tax free given if they presented their passport upon purchase proving they’re merely only a visitor, that won’t work on expats though). Those countries usually have tax refunds when visitors are leaving (basically reclaiming VAT whilst at the airport).
I fundamentally disagree that it is impractical not to put it on the price tag. Every store prints their own price tags and puts them either directly on the item, or on the shelf. It wouldn’t be hard to just make that price different to reflect the tax. We already do it with gasoline.
Every POS is also calculating those taxes anyway to print on your receipt. The only reason prices on tags don’t include tax is because it’s not required and smaller number is better.