What phone do you have? Galaxy S8
What plan are you on?
Does your plan include data, or just talk & text? Talk & Text
When in the phone mode the display disappears in a matter of seconds.
Example: I bring up the phone key pad, dial the number, party answers. If the answering party has a directory, i.e. dial 1 for English, dial 2 and so forth, by that time the display is blank, it will stay on if I swipe the screen continually. I have set display for “always on” does not help.
I have had the phone about a year and it has always been this way. Samsung has not been able to help, I do not think they understand what I am saying.