@Garry-Davis Thanks for the information. Indeed not old 
Just a basic model (nothing wrong with that) but therefore it's just a slightly lower resolution than what we expect as minimal.
As example, we aim to visually support all resolutions from basic iPhone 10 and upwards. But as this is a budget phone, the resolution is still lower than that iPhone (which is from 2017).
Now this puts all those requests "just put another button on the screen" in perspective. As doing that while supporting a whole range of devices is quite difficult.
In good news, we are reworking some parts of the app to include less of those buttons on screen / not such big app bar at the top ensuring slightly more space
But that still needs quite some work.