If budget is tight, play the free mobile version (with ads) or hunt for a used physical cartridge. The extra $10-20 you save compared to a pirate’s risk is not worth losing your online access or bricking your Switch.
“Nintendo doesn’t care about small indie games.” False. Nintendo has a dedicated anti-piracy team. They have issued DMCA takedowns against hundreds of NSP sites, including those hosting this very game.
Sometimes, developers sell their games directly through their websites. This can be a good alternative to the eShop and might offer additional promotions.