Malaysia doesn't even have an E-Shop actually. There is a website but the games there only show information about the games, no option to purchase.

I use the JP e-shop, their currency is a bit weak at the moment and they have a lot of games on discount. Most games support English as well. If you have doubts, check this link check if the game you're looking for has the language you want:
https://www.perfectly-nintendo.com/nintendo...ption-in-japan/

And yes, you can change the country at any time.