Thank you very much! Are you refering to a specific app or just in general? The mechanical button on the phone's bottom panel will always take you to the home screen. Unless, of course, there is a bug that I am unaware of. If that's the case, I would appreciate if you could describe it.
Just in general - it could be that I'm playing on a mac, but I'm not seeing but button to go to the home screen - I'll try on a windows and hopefully it'll be there!