Attached part of the syslog where the problem starts to appear.

Question: Should I backup my flash and transfer to a new usb? Will I have issues due to the flash drive failing?

 

Jan 24 00:43:29 NAS kernel: critical medium error, dev sda, sector 21567296 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2
Jan 24 00:43:29 NAS kernel: I/O error, dev loop1, sector 78928 op 0x0:(READ) flags 0x800 phys_seg 21 prio class 2
Jan 24 00:43:29 NAS kernel: SQUASHFS error: Failed to read block 0x268a6b0: -5
Jan 24 01:39:03 NAS flash_backup: adding task: /usr/local/emhttp/plugins/dynamix.my.servers/scripts/UpdateFlashBackup update
Jan 24 02:06:02 NAS nginx: 2025/01/24 02:06:02 [crit] 15465#15465: ngx_slab_alloc() failed: no memory
Jan 24 02:06:02 NAS nginx: 2025/01/24 02:06:02 [error] 15465#15465: shpool alloc failed
Jan 24 02:06:02 NAS nginx: 2025/01/24 02:06:02 [error] 15465#15465: nchan: Out of shared memory while allocating message of size 11702. Increase nchan_max_reserved_memory.
Jan 24 02:06:02 NAS nginx: 2025/01/24 02:06:02 [error] 15465#15465: *317140 nchan: error publishing message (HTTP status code 500), client: unix:, server: , request: "POST /pub/devices?buffer_length=1 HTTP/1.1", host: "localhost"

It is a flash drive problem, you could try reformatting it first, or just transfer to a new one.