NVMe is dropping offline:
Sep 5 13:38:54 Unraid kernel: nvme nvme0: I/O 771 QID 7 timeout, aborting
Sep 5 13:38:54 Unraid kernel: nvme nvme0: I/O 772 QID 7 timeout, aborting
Sep 5 13:38:54 Unraid kernel: nvme nvme0: I/O 773 QID 7 timeout, aborting
Sep 5 13:38:54 Unraid kernel: nvme nvme0: I/O 234 QID 1 timeout, aborting
Sep 5 13:39:24 Unraid kernel: nvme nvme0: I/O 771 QID 7 timeout, reset controller
Sep 5 13:39:54 Unraid kernel: nvme nvme0: I/O 0 QID 0 timeout, reset controller
Sep 5 13:40:57 Unraid kernel: nvme nvme0: Device not ready; aborting reset
Sep 5 13:40:57 Unraid kernel: nvme nvme0: Abort status: 0x7
### [PREVIOUS LINE REPEATED 3 TIMES] ###
Sep 5 13:41:27 Unraid kernel: nvme nvme0: Device not ready; aborting reset
Sep 5 13:41:27 Unraid kernel: nvme nvme0: Removing after probe failure status: -19
Sep 5 13:41:58 Unraid kernel: nvme nvme0: Device not ready; aborting reset
This sometimes helps, some NVMe devices have issues with power states on Linux, try this, on the main GUI page click on flash, scroll down to "Syslinux Configuration", make sure it's set to "menu view" (on the top right) and add this to your default boot option, after "append" and before "initrd=/bzroot"
nvme_core.default_ps_max_latency_us=0
Reboot and see if it makes a difference, if it doesn't you can try the latest beta, newer kernel might also help, if not try a different model NVMe device if possible.