Since you're new, first thing you should do is grind and upgrade one. Even if it was slightly nerfed KRIG still slaps, AK47 if you learn to control recoil or use it as a close-midrange weapon. GRAU and M4A1 are always viable long range weapons.
For close many will do: Bullfrog, Gallo, Mac10, CW MP5.
The MW AK47 is my go to weapon in WZ. It has some recoil, but it has a very fast time to kill and slaps hard with the proper attachments. You should be able to search something like ?Best Warzone AK47 loadout and find a youtube video or gaming article with the best attachments. Let me know how the load oit works for you! Good luck!