I have heard that many first-hand memoir and diary accounts of life during the thirty years war exist, are any available in English or only in their native languages and if so is it possible for a layperson to obtain access to these materials?

Helfferich, Tryntje (ed. & trans.), The Thirty Years War: A Documentary History, Indianapolis: Hackett, 2009: includes two of such memoirs, that of Soldier Peter Hagendorf and of Civilian Hans Heberle respectively, in English translation, though I'd also recommend also to read English translation of Grimmelshausen's Simplicius Simplicissimus (1668) (linked to Penguin Classic English edition) to grasp the atmosphere of the 17th century after within the end of the thirty tears war.