The Arma series is the most realistic online fps you can get. The American Military use it for crying out loud. To succeed you need teamwork, planning, strategy, thoughtful weapons and support from the air and ground and if needed the sea.
Search and destroy is not realistic at all. You won't find quick scope's etc or whiny little kids on Arma just people who actually want to play as a team and help each other out. Failing that there is insurgency which is bit less tactical etc and planning doesn't happen be ut it is still realistic.
Then its Battlefield and then CS GO. Failing those, Payday 2 requires a lot of teamwork if you play it with friends and requires co-ordination. You can get all of these games of Steam.
Arma has a variety of modes and mission you can create such as hostage rescue, CQB training etc. Insurgency has game modes like Battlefield and COD but more realism and tactics. The same goes for CS GO. Hope this helps.
Oh you want realistic; try America's Army it is so realistic you will feel really tried after playing it, just like a real soldier in the Army.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.