This is annoying. I have black bars about 2 inchs in margin around my picture on pop. The resolution says 1920x1080, which indeed it is on a 1080p tv. Now my problem with the bars is not present on windows. I have messed with the TV to change from 16x9 to fit the screen and the border is still there. I vaguely remember ubuntu had an option to optimize for tv use I thought I might give that a shot, but I dont have that option in the displays settings.
Like @nbm suggests, it might be on the TV side; if you do Ctl+Alt+F3 for a terminal screen, does it look to use the whole screen?
If the cursor/writing is offset like the black bars are still there, I think it might be TV side.
If the writing is the very top left, the like @w.meri suggests, there is probably a setting to change.
I just figured it might be the drivers. There were the open source drivers that comes preinstalled with popos. I did the nvidia proprietary ones and it is fixed. F for open source.
Keep in mind this tv is 10 years old or just about and the popos box I am using is 2nd gen i series. So old hardware. Even the gpu is shite. It is a gt 610.