While not strictly military (according to the designers Eaves and Sternbach, they were not "escort" vessels, more like "sports car heavy cruiser"), and usually used for diplomacy and exploration, Sovereign still packs a punch, more than Galaxy-class vessels, due to how many torpedo launchers they have. They're also tougher (finally, a non-custom ship with real armour, even if only around critical areas). It's overall a better ship, stronger in battle, even if that's only because it's more technologically advanced.
They were introduced to service before 2373, and the Dominion War lasted until 2375. So why weren't they used in battles?
I can't remember where, but I read that they were "used to put out diplomatic fires". Why not use smaller vessels for these tasks, like the Intrepid, which was sent to Romulus, arguably a mission much more important than any of these unspecified "diplomatic fires"? The only time we saw a Sovereign in Deep Space Nine was on a computer screen, a silhouette.
What were the Sovereign-class vessels doing during the war? There had to be a few. There was the Sovereign itself, then the Enterprise, and some I can't remember by name.
I'm looking for both in-universe and tv explanations.