Typical scenario:
Tap on entity on Dashboard
Tap on Show More to see longer history
No way to come back to what I was doing on mobile.
On the desktop, there is the back button, but in the mobile app (iOS) there is no way to get back without navigating to the Dashboards again.
is there a back button in the deskop / browser app?
[except the button provided by the browser - this wont work when in kiosk mode]
There isn’t either – but on desktop it is fine. The mobile view should deal with this through a swipe action or some such.
it’s not 
Running HA in Kiosk mode (for example Chrome Browser → create app) does not have any “paga back” button… so there should be a back button be available at all
I have to say that I have, rather embarrassingly, only just discovered that a two-finger swipe on the iPhone from the History page brings you back to where you came from.
I guess that takes care of most of the problematic situations for me.
I noticed the same.
But:
If you run HA in a Kiosk Browser mode, for example, you don’t have any “browser-back” buttons - nor any “swipe back” option.
Therefore, a Back button in general would be the perfect solution.