I would consider using these textures in PVP cheating as they make using the scopes significantly easier and will give you an upper hand over players without these files.

Theoretically servers running sv_pure 1 or 2 may kick you for using these textures, at which point you will have to replace them with the original if you wish to play on such servers, although modded support for sv_pure is iffy at best, not sure if CHECK_CRC ever works for files not packaged with the VPK package format.

Download the replacement textures from the google drive link

Navigate to the game's files

Drag and drop the downloaded folder into the inner EYE folder.

You will know you did it correctly when a prompt asking you whether you wish to replace existing files appears. Click yes

If you were in game when doing this, run the following commands

Replacement Textures (Google Drive)[drive.google.com]