Without the ability to revive, I totally agree combat could be tough. I dint use the karmic dice, just pure random. You sometimes just end up on a bad luck streak and it’s rough. As long as you can finish the fight, you’re fine though. You may spend more resources than you wanted, but that’s how it goes. (I also don’t just long rest after every fight. I try to play like tabletop and only rest when it’s critical. It makes spell slots much more of a resource to manage and spend.)