Repeat after me: ZRAM is not swap. ZRAM uses the same OS interface as swap does, and that interface is called "swap" but really is more about composing system

Repeat after me: ZRAM is not swap. ZRAM uses the same OS interface as swap does, and that interface is called "swap" but really is more about composing system memory out of tiered backing memory. One of those tiers can be swap. With ZRAM and no swap, all your system memory is volatile. As long as Linux requires nonvolatile system memory to hibernate, it will be impossible to hibernate in this setup.