Then you most likely never had a TFT running in anything but its native resolution I assume.
Otherwise you most likely would know that there is only a very small minority of screens that do NOT destroy text in a way that gives you bad headache in less than 2 hours if you do not run the screen in native resolution (same aspect but smaller resolution does not solve that as well)
Nobody ever would try to set his desktop resolution to something different than native TFT (and if he does then most likely for good reasons -> crap graphic card for example)
In either way, the desktop resolution is the resolution the user wants to be in most likely, you can still offer an option menu afterwards in case he needs it.
Otherwise you most likely would know that there is only a very small minority of screens that do NOT destroy text in a way that gives you bad headache in less than 2 hours if you do not run the screen in native resolution (same aspect but smaller resolution does not solve that as well)
Nobody ever would try to set his desktop resolution to something different than native TFT (and if he does then most likely for good reasons -> crap graphic card for example)
In either way, the desktop resolution is the resolution the user wants to be in most likely, you can still offer an option menu afterwards in case he needs it.