Hello dear friends
Through this method, I will tell you how to remove the black bars of the game and play in full screen without lag. (This method works in all modes and does not harm the game)
Well, friends, let's proceed according to the following steps:

1) we find the Windows registry through Windows search

2) run as administrator registry editor

3) Enter this path in the search tab of the Windows registry
Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\GraphicsDrivers\Configuration\

4) In this step, you will probably find one or more different folders with different names, open all the folders under the Configuration sub-set, in the next step, enter its sub-sets (in all cases, the sub-set is a folder with the name= 00)

5) After opening the folders with the name 00, you may come across other folders with the name 00, open these folders as well and look for a file called Scaling in the right part of the Windows registry screen.

6) Well, this is the last step!
Select the Scaling file and change its number from 4 to 3. (Note that if your sub-folders in the Configuration folder are more than one folder, you must open all the 00 folders separately and Scaling it from 4 to 3. change it.)

important points:

After completing these steps, all the black bars in the game will disappear

Your resolution will change to aspect ratio 4:3

Your FPS has increased and you may have better aiming

> Please do not change anything else