I’ve personally gone with an N100 Mini PC running Proxmox and two of these daisy-chained (purchased on sale). https://www.amazon.com/MAIWO-Enclosure-Cooling-Storage-Expansion/dp/B0D28Q187R/
The MAIWO DAS uses garbage JMicron firmware by default, and there are significant issues with their sleep functions. Because of that, it took me forever to figure out why SnapRAID kept failing mid-sync. Fortunately, new firmware seems to have fixed their issues and they’ve been rock solid ever since. I specifically had to update the firmware for all 4 of the USB controllers on each DAS.
Direct link to firmware that worked for me. https://gbatemp.net/attachments/bin-16028_jms578_std_v00-04-01-04_self_power_odd_20190611-zip.230929/
JMS578_STD_v00.04.01.04_Self Power + ODD.bin
MD5: 7701fb7a968e3ad4ca926dd7854806ff
Firmware updater tool for Windows found here. I ran this from a Virtualbox Windows 10 VM inside my Arch install: https://gbatemp.net/attachments/jmicron-jms578-sata-crystal-enclosure-fwupdate-zip.216335/
FwUpdateTool_v1_19_16_24.exe
MD5: 735ec8d9f99c457ce793739480c55706
Mirrors for posterity:
https://files.catbox.moe/e4121s.zip
https://mega.nz/file/OJAX2KhQ#67kIDJun92nqi56mFur_9vALSi2yTJXXv7ew5pYSJVY
Blog post detailing firmware update procedure for an external drive: https://ralimtek.com/posts/2021/jms578/
Detailed post on JMS578: https://gbatemp.net/threads/how-to-update-firmware-of-jmicron-jms578-usb3-0-sata-enclosure-black-screen-lock-music-stop.569158/
Alternate FOSS software for flashing I found later, but never used. https://github.com/BertoldVdb/jms578flash
Text, photos, CT scans, stats, testing, graphs, etc. Still a work in progress, but it’s come a long way.
https://www.lttlabs.com/