Hello,
1) Don’t use author directory because you will lose your translation after theme update, use System directory https://prnt.sc/zl7abi It’s mentioned in theme documentation https://xstore.helpscoutdocs.com/article/30-base-theme-translation
2) You used the wrong lang xstore-de_DE_formal.po instead of xstore-de_DE.po 3) Translate the mentioned strings https://prnt.sc/zl7pb7 and check frontend again.
Regards
