Hi Medyen
Sometimes video member is set by the manufacturer and cannot be changed. You can try loading the BIOS and see if there any options to change it there.
See if this article helps point you in the right directly:
How to Increase a Dedicated Video Ram (VRAM) on Windows 10 ...
https://appuals.com/how-to-increase-a-dedicated...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.