The Nintendo Switch eShop is totally region free (however, credit cards don't seem to work overseas, you should buy an eShop card to redeem) : r/NintendoSwitch
Using GCash to Pay for your Nintendo eShop Games (Switch, Switch Lite) - GCashResource
How to get Nintendo Switch Online without a credit card | iMore
手把手教你如何在任天堂eShop里購買數字版遊戲- 每日頭條
The Nintendo Switch eShop now lets you store your credit card info | VG247
實測】申請張MCO 金屬卡跨區買Nintendo Switch 遊戲吧! - FlyAsia
Using GCash to Pay for your Nintendo eShop Games (Switch, Switch Lite) - GCashResource