Hell Let Loose would be my number one recommendation. It has a sophisticated comms system and a great gun model. The servers are 100 people, so there is plenty to shoot at and cooperate with. It is not an arcade and plays more like Squad. I really have no complaints about it except that it is an FPS and I generally do not play them often.
Post Scriptum is along those same lines as Hell Let Loose, but it seems to be less polished. I do not own it so I cannot comment to a great extent on it.
Battlefield 5 is a WWII Battlefield. It is a bit of an arcade and has your typical Battlefield models, ballistics, and issues.
Red Orchestra 2 is aging, but for a very long time was the best WWII FPS on the market. It is still great, although it looks 10 years old because it is.
Finally, Heroes and Generals is a lot of fun. This game was an ambitious attempt at a better WWII Online and did not miss by much. You choose a country to play as in the war, which is real time and dynamic. All of the soldiers, tanks, planes, etc. are owned by players and the players move their units around the map. I'll not explain it away here, but Heroes and Generals is free and worth checking out.