Just an update in case others stumble across this.
I really honed in on the HBA, backplane, and SAS cables since my NVMe pool didn’t seem affected by this.
However, as time went on, I started getting system hard lockups. After moving PCIe cards around and troubleshooting, I finally ran a Memtest and was met with over 3000 errors within 1 minute of running the test.
Turns out, 4 DIMMs of DDR5 require significantly reduced speeds for stability. I read this before my build and made sure XMP was disabled and that memory was set to the Intel official non-overclocked speed of 4000MT/s. After reducing the speed to 3600MT/s, no errors registered in Memtest.
I am running a new scrub with the 3600 speeds and assume I’ll be met with checksum errors again on the first scrub since the RAM issues could have caused some data loss, but that a subsequent scrub should reduce no errors.