Currently, Android 12 (or less than 12) does not let you customize display language for apps. Apps blindly follow the OS-wide language.
Although English is not my native, I prefer English over my native one (Korean) when the app's traslation is not good. I think it's less time-consuming that you add the option than that I contribute on translation. Translation requires elaborate work!
WorkingHours version: 2.7.9
Operating system: Android 12