Ok, at least your CPU is responding as it should when you alt tab or just hang in the menu.
Can you confirm that the entire installation folder is in your exclude list in your anti virus?
To disable full screen optimization: https://winaero.com/blog/disable-fullscreen-optimizations-windows-10/
There a couple of other things you may want to try.
First you should tweak your power plans in windows and in nvidia control panel.
In windows try changing your PCI express power -> link Link State Power Management to off.
In nvidia control panel change the power management mode to maximum power.
You can do one at a time and see if something changes.
Also if you are using G-sync try to enable/disable it depending on what you use today.
Further you should make sure you have the latest windows build considering some previous build have given some people issue.
On thing you can also try but you should not use it as a permanent fix is to disable HPET.
You do this by opening command prompt and type bcdedit /deletevalue useplatformclock
Do enable this again enter: bcdedit /set useplatformclock true
If you do this and it fixes your issue note that it may mess up for other games so its important to enable it after each battlefield session.
And do you happen to have access to any other game using the frostbite engine? Anthem, Battlefront franchise, Fifa, previous battlefield titles
If you do can you check if you have any abnormal gpu usage there. Fifa probably not the best example since its not too demanding btw but if that games goes 100% cpu as well then your system really doesnt like frostbite.