Where is my 800MB of RAM gone? Ubuntu is not detecting all my memory

I am a bit confused about my 800mb out of 2gb ram gone ? I already test the following command,

 sudo dmidecode | grep Size | grep MB

Size: 2048 Mar

free -h

cat /proc/meminfo | grep Slab

Stab: 114756 kB

dmesg | grep stolen

25.169226] pci 0000:00:00.0: detected 32768K stolen memory

sudo dmesg | grep -i 'Memory:'

[0.000000] PM: hibernation: Registered nosave memory

[mem 0x00000000-0x00000fff]

0.000000] PM: hibernation: Registered nosave memory: [mem 0x0009f000-0x0009ffff]

[ 0.000000] PM: hibernation: Registered nosave memory: [mem 0x000a0000-0x000eefff] [ 0.000000] PM: hibernation: Registered nosave memory: [mem 0x000ef000-0x000fffff]

[ 0.000000] PM: hibernation: Registered nosave memory: [mem 0x4ff4a000-0x76685fff]

[ 0.000000] PM: hibernation: Registered nosave memory: [mem 0x76686000-0x76785fff]

[ 0.000000] PM: hibernation: Registered nosave memory [mem 0x76786000-0x777fefff]

[ 0.000000] Memory: 1172084K/1309604K available (16393K kernel code, 4374K rwdata, 10792K rodata, 3228K init, 6580K bss, 137260K reserved, OK

cma-reserved)

[ 0.025754] Freeing SMP alternatives memory: 40K

[ 0.955369] Freeing initrd memory: 63764K

[ 3.063509] Freeing unused decrypted mory: 2036K

[ 3.064575] Freeing unused kernel image (initmem) memory: 3228K

[ 3.065843] Freeing unused kernel image (text/rodata gap) memory: 2036K

[ 3.066450] Freeing unused kernel image (rodata/data gap) memory: 1496K

free -k; vmstats | head -n 1

 1244944 K total memory


sudo lshw -c video

*-display                 
       description: VGA compatible controller
       product: Core Processor Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 02
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:30 memory:90000000-903fffff memory:80000000-8fffffff ioport:5060(size=8) memory:c0000-dffff

and my graphics driver is using 256mb of ram and I have BIOS Here is the screenshot of my sysytem monitor,

I also had tested the memtest and it is showing 1.2 gb of ram only.
I also had ubuntu 22.04lts long side with ubuntu 20.04Lts and when I compare ram given in settings>about of 20.04Lts it shows 1.2 gb but in 22.04lts it shows 2gb. I also searched whole askubuntu about this and didn't found anything about my problem. If you want any other information know me in the comments. Please give me the solution of it because I cant do anything on 1.2gb ram instead of 2gb ram.
I also want to say that earlier it shows 1.9 gb insted of 1.2 gb which is now.

Integrated GPU uses system RAM. This is normal.

So your 800 MB are used by the Intel GPU.