Thank you for getting back to us with the additional information, and I appreciate the excellent detail you provided and the annotations shown in your photo.
Based on that information, I believe you may just need to use the ‘Auto-adjustment’ option within the Samsung display on the left-hand side of your desk to resolve the problem.
To expand further, when a display is connected using a VGA video cable there are some cases where the display has to be adjusted so that the image fits properly within the display.
Most displays have an ‘Auto-adjustment’ feature built-in to the display that can (as the name implies) automatically adjust the image.
The manual for your display --> http://downloadcenter.samsung.com/content/UM/201906/20190618104444943/BN46-00552H-Eng_for_India.pdf shows how to access this option on page 10:
If you use the auto-adjustment option within the affected display as shown in the manual, does that help resolve the problem?
If you are unfamiliar with this process or need to make further manual adjustments, I made a short video that demonstrates this process in action here --> https://youtu.be/KYyZgocwvms
The display shown in my video is a Dell U2412M display, but the concepts demonstrated are the same.