How can I close my current app via a keyboard shortcut? On Windows or Linux, ALT+F4 closes the application (well, window) that is focused. Is there anything similar on Android (9.0 Pie) ? I have a phone with a keyboard but without function keys. I find it hard to believe this is impossible yet I was unable to google it out.
In Android 9:


To go home you can press "Windows key" (if you have a keyboard for
Windows) plus "Enter".
Press "Win key" plus "-". Android will show you all shortcuts.
Other way, if you already have plugged your keyboard, go to
"Settings" and search "Physical keyboard", there you will find
configuration needed.