I've been using TrueNas with a nightly sync to Backblaze for years and I like it.
It used to be called FreeNas and used FreeBSD. Now the BSD version is called TrueNas Core, and a new Linux based version is called TrueNas Scale.
I would go with TrueNas Scale if I were starting a new one today. You probably won't use the "jail" functionality immediately, but they're super handy, and down the line if you start playing with them, you'll run into fewer compatibility issues running Linux vs BSD.
The disagreement here might be a semantic one. When people say "swap" they're usually referring to the swap partition on disk, not just any memory that can be used to "spill" to.
What you are describing with zram serves a fundamentally different function from swap space. If the OS dumps its memory to swap, the PC can lose power and still recover. If it compresses LRU memory to zram, and loses power, it cannot recover.
Both are useful in low memory situations, but swap covers more than that. Most familiar with swap space would agree that its location on a nonvolatile disk rather than in volatile memory is critical to what makes it "swap" space.