In the past, I’ve floated the idea of implementing a rez timer every time they die but I understand that’s probably tricky to implement and they’d still just die instantly in labs/other endgame content, even with max ele/phys resist. If they were made unkillable, you run the risk of cheese. The only solution that seems viable would be to make them untargetable. They cannot he killed but they cannot take aggro. This would prevent glass cannon builds from exploiting a meat shield.
Would it be possible to make them untargetable? To make mobs ignore them entirely while they fulfill their basic damage-dealing prerogative?
Feel free to stress test the idea.