I recommend implement simple DRM for your game with itch.io API like checking whether user owns the game with the provided credentials.
You can give choice to users to decide storing their credentials on their computer so they don't have to type password every time.
TBH if your game is worth playing, people would still play with the login system/DRM.
There are people who don't like DRM but I think they should understand there's a reason why it has showed up in software industry.
Especially for indie game developers, every small coin matters.
If someone just decides to share what he bought, then it is really difficult to stop the sharing.
Some people talk about relying on law, but that only works where you live most of time. Also it costs a lot for a law suit.
Therefore simple DRM wouldn't harm anyone.

Ok, Thank you! :)

Yes, South Korea asks for a VAT report and I have done that for steam.
Normally the online store should be handling VAT so I don't have to worry about it.
But I am just checking because I will be reporting to South Korean tax authority, that I earned money from South Korean customers by selling software through itch.io and itch.io paid VAT.

I talked about the language support, because if I support those languages then there will be buyers from the countries with first language as Korean or Japanese.

I might sell my games/software in Japanese or Korean.
Does itch.io handle VAT for Asian countries as well?