I’m not sure it’s going to work like you hope it will. Your enclosure can run ‘raid’ but zfs doesn’t like raid. As far as ‘jbod’ thru one esata cable…thats not how zfs likes it either.
Your best bet is to buy a m2/nvme to 5 sata port adapter so zfs can distinguish each drive. But then… the question is if your enclosure allows that.
I love mini pc’s but for zfs there’s not a lot of wriggle room. High end ones have dual nvme ports allowing for zfs mirror. Other than that you’ll have to go said sata_nvme + an enclosure that powers all disks but allows for individual sata cables. It’s gonna be clunky macgyvering too.
I bought a HP elitedesk G3 800 mini pc and managed to install an ‘M2 to ethernet card’ in the wifi port. Avoid HP G2 mini as they have a capacitator too close to the M2 wifi slot.
It’s a bit macgyvering to secure it to the rear of the chassis though. You’ll need 2 longer nvme screws and some hard plastic to secure it to the mobo.
Its supposed to be called betterFS but Jim Salter keeps calling it butter FS. Doesn’t really inspire confidence. At least it’s gonna need… a better name
Something I’m looking at myself is HP elitedesk 800 gen3 Tower. Mobo has 5 sata ports in addition to 1 nvme port. It takes 6/7th gen cpu so you could reuse your current cpu. 4 ram slots DDR4@2400.
What is especially appealing is the 5.25 slot for which icydock has a powered bracket that takes and powers 4 SSD disks. (Edit: ejectable too). Sure the chassis has internal space to accomodate even more HDD.
With Proxmox on the nvme + some raidz zfs action would make for a nice HCI setup. My next build and might inspire yours.