Wars moved poets (and even soldiers) to transform their experience into poetry, although we think of this experience as universal because it records common human sufferings, however, the difference in time and place (and even politics and worldview) could influence the way this experience is rendered.
You correctly identify that time and place influence how poets reflect, and review, their work. British Poet Percy Shelley makes a similar observation as poets respond to the world around them and try to process continuities and change. For that reason, there isn't a specific single answer beyond "it depends on the war." Typically the outcome of the war and its political context makes a huge difference in how different types of poetry emerge; American poetry in Vietnam will be vastly different than poetry from the 1940s. Let's take 1945 Britain and the United States of America as another example. British poetry in 1945-1950 was very much "a relief" rather than triumphant whereas you see more triumphant messages in a lot of America works (at least until the Cold War) kicks in.
For specific examples and a breakdown, See Brian Bond's Britain's Two World Wars against Germany: Myth, Memory and the Distortions of Hindsight or David Aberbach's National Poetry, Empires and War.
Two poems that stroke me for the similarities they share in the presentation of an encounter with the enemy; these are Wilfred Owen's "Strange Meeting" and Mahmood Darwish's "A Ready Made Scenario:سيناريو جاهز"; the former is British and the latter Arabic.
We might think that the similarities are natural since "they record common human sufferings". However, the closeness of the imagery and even vocabulary between these two poems left me with a question:
Is poetry an expression of opinions or facts?
As for how the two dimensions of place and time influence the poetic presentation, I tend to see that poets view experiences through (a) filter(s) or screen that would transform an experience into abstract imagery or sometimes solid symbols. This process could foreground the similarities rather than the differences in poetic presentations about traumatic human experiences as a symbol or an image is less likely to convey nuances.
You might want to have a look at the two poems:
http://www.adab.com/modules.php?name=Sh3er&doWhat=shqas&qid=79620&r=&rc=6
https://www.poetryfoundation.org/poems/47395/strange-meeting
Well i read different war poems . Actually all of them express the pain and suffering.The use of profound images do make the difference.