It is not easy to do this. A friend learned the hard way. She was visiting the US and needed a laptop. Their online shop doesn't take foreign cards, probably to prevent price arbitrage. Lots of Reddit posts confirm the problem. You can always go to a bricks-and-mortar but model selection is more limited, especially in case of exotic SKUs.
When VAT incentivises people to essentially take their holidays outside the EU - not even incentivises, subsidises(!) - VAT's too high.