People on YouTube are playing games in English. I guess they are using the US eShop. I register an account in the US. I try to pay another subscription. It needs a US credit card.
Sigh.
I have a Swedish credit card. I don't actually have the plastic (because they want to send it to my official Swedish address and I don't have one) and I don't know my current expiry date, but it's still successfully paying for a Swedish SIM card and some other minor recurring costs.
So maybe I'll try again later to get a Swedish eShop account with the card I kind of have. Or maybe the Swedish eShop is less picky and accepts a HK credit card. We will see. The saga continues.