I know that there are themes directly adapted for multilingual (I no longer have the names in my head). And then you have a lot of apps that do that like Langify App!
But is that just a translation app? With these kind of apps, i can also change currency and for example shipping prices per location? So really 1 backend for 4 front ends in 4 languages?
For currency conversion, you can check out ‘‘Best Currency Convertor’’ in shopify app store - it can change the currency of the website depending on the location of the visitor.
For shipping settings, those can all be modified in shopify shipping settings ( shipping rates based on country )