It was shown repeatedly that Jem'Hadar stripped down to their base desires would do little other than fight. That was it. They were literally designed to fight above all else and are generally only kept in line by an intentional metabolic deficiency which the Ketracel White provides.

Jem'Hadar "downtime" was combat training against prisoners. Or other Jem'Hadar. They didn't eat, they didn't sleep, they didn't have sex. These were all literally spelled out in DS9 multiple times and yet this new shitshow yet again decides to shit all over decades of lore because new thing must be unique and shiny and have grrlboss characters with mysterious backgrounds to create drama and still be the bestest person in the room.

The franchise pillaging fatigue is real.