Yesterday I encountered the artistic term 'Sturm und Drang' (roughly: storm and stress), a term that describes the literary and artistic movement influenced by Rousseau. It has also been co-opted in English to an extent where it can more generally be used as a noun to describe a "Turbulent emotion or stress" (Oxford Languages).
Out of curiosity, if this term were to be pluralised, should we use the German pluralisation methods? If so, it becomes 'Stürme und Dränge', but I don't believe any dictionary lists this as an appropriate plural noun.
Is it then proper to Anglicise the plural noun to 'Sturm und Drangs', or is it better to allow 'Sturm und Drang' to denote a plural noun in English despite the singularity of the German.