Recommended cache pool setup for 2 pairs of NVMe SSDs. BTRFS/ZFS, stripe 0 or 1?

So I have an fresh unraid build with 4 nvme slots and my array. I am trying to decide how to allocate my cache pools.

I have:

• 2x 256GB nvme (generic brand) - pcie lanes for these two are limited to sub 1000-1500MB/s
• 2x 2TB nvme (Hynix P31 Gold) - pcie lanes for these two are limited to sub 3000-4000MB/s

I was thinking of putting the generics as appdata for my dockers and maybe low performing VMs (just want to run Win10 or ubuntu for random stuff) and then my P31s as download cache to eventually write to my array. The reason why i did this is because I don't think my generic nvme ssds have DRAM, so sequential writes might get throttled hard.

I plan to use the download cache as a buffer if i need to transfer stuff between my NAS devices (or should I just write directly to HDD if i do large sequential writes and temp turn off cache?)

I plan to torrent often and download series/shows/etc.

For my filesystem, I am only given 2 choices: ZFS or BTRFS

I've been reading horror stories about both file systems (esp BTRFS, but a lot of negative comments are months old), I just want something that works performant and isn't going to corrupt on me for no good reason. I already plan to schedule mover to replicate my cache data back to the array (maybe daily or weekly) so if the cache pool dies, i can easily just replace, redo, rebuild/copy back.

I think for my main array I am just going to go BTRFS. any reason I shouldn't?

But I am getting stuck on which FS to choose and also if I should be using the raid0 or raid1 allocation method.

Compression ON? or Off?