How much time does The New War take?

Depends how fast you rush through it and if you get stuck anywhere or not.

3-5 hours is typical. I'd say ~4 if you take everything in but don't particularly get stuck on anything.

Perhaps 3-6 hours, 3-4 is reasonable, 6 would be the worst if you keep getting stuck in some parts.

While you're locked out of doing other stuff while the quest is active, you're given a place in-between missions where you can log off. You don't have to do the entire quest in one sitting, and you can definitely finish the quest in one day.

Watching cinematics and enjoying some bits, around 4 hours.

About 4-5 hours if you play chill, can be done faster

Took me about 5 hours but I got stuck in couple of places where I didn't know what to do.

Do note that there weren't any guides when it was released so now you can just google if you get stuck.

Took me around 5 h

4-5 hours is probably the average.

Most people probably do it in about 4-6hours.

Keep in mind, you don't have to do it in one sitting. There's numerous save points. However, as the warning tries to inform you, you can't return to the "normal" game until you complete the mission.

Kinda depends on how long it takes you to adapt to some of the gameplay/boss fights. Once you get the hang of it, they're super easy. Just have to get the right balance of movement/dodging, and shooting. Don't feel like you need to get "perfect" shots all the time, just fire off a quick shot to do some damage and keep moving. Weave attacks in-between dodges and you'll be done with the boss fights in a couple of minutes.

My first time playing took 5-ish hours.

You can exit the game at regular intervals though.

I've heard 4-6 hours from a bunch of people, I was a little shocked when it ended up taking me more like 10. Definitely a few spots that are pretty rough.