Hmm lots of suspicion at the new drive. I wasn’t as deliberate as you described, but that new ssd now has arch on it and boots fine.
I guess maybe I’ll ask this question. Should I be able to just unplug an optical drive, and plug in anything else into that sata port without linux hanging? I wouldn’t expect the new drive to DO anything until it’s partitioned/formatted/mounted etc. but can I just swap components and expect to be able to boot?