I don’t know about the Ubuntu LCX. I don’t container much.

I’d do this with a virtual machine and TrueNAS. Those are just the tools I like to use. The TrueNAS Scale ISO will install qemu-guest-agent, so you don’t need to worry about drivers. Make sure to build it with Virtio SCSI Single disk controllers. Use one 50gb OS disk for the install. Add huge data disk(s) after the install.
Promox Disk options … SSD emulation, Discard, IO Thread, No cache … and I use Write Back (unsafe). Use the Virtio NIC.

And try it again. Hopefully faster this time.

Been working on a jukebox VM. This seems like it will mesh well. Got LMS installed. Muddling through the rest. https://community.home-assistant.io/t/how-to-build-a-lms-based-whole-house-audio-system/436016