I will upgrade my ram to 24gb soon.
Do not waste your money on this laptop.
Open the Limit Reasons window. Your new laptop has a BD PROCHOT throttling problem. The main screen of ThrottleStop shows that BD PROCHOT is locked in the enabled position which is typical of almost all 12th Gen and newer laptops. Unless you can find out what is causing BD PROCHOT throttling, your computer will forever be stuck at 399 MHz. ThrottleStop reports this speed correctly. The Task Manager does not.
Sometimes BD PROCHOT problems are caused by using a generic power adapter or a generic battery. Hard to recommend replacing both of these because there is no guarantee that will fix the problem. Someone sold you a dud. You might be best off getting rid of your new laptop.