Lots of sites tell you that you should be "re-purposing" old Android phones into something useful.
I admit there are some useful things they could do. Various kinds of clocks and weather forecasters are obvious; also a remote control for your smart thermostat or lighting.
However, none of these sites deal with the main difficulty for many of these. Which is, of course, old Androids do not rotate the home screen into landscape.
This caused me no end of frustration (well - OK, several hours - but it felt endless) when I wanted to make an old phone a wall clock/weather monitor.
One way to fix it: Use Nova Launcher. It supports landscape home screens, even on older devices.
Google Launcher also did so, but is apparently discontinued. It also populated the home screen with extra crap that Nova does not have.
Nova can also get rid of the quick-access apps and the status bar. It can't get rid of the home/back buttons, as those are part of the OS.