There is that. But, OWC currently recommends DiskWarrior for the SoftRAID array I just purchased from them, and it did work to recover my 4-drive array three weeks in.
I’m trying to recall what Disk Utility said about the same array, but as I recall it was on the order of “huh, everything looks fine to me—wait, where did it go?” as it unmounted the array and wouldn’t mount it again.
As for your general advice, Adam, thank you. My current plan is to move the 2012 iMac to one side of my desk, install a 2019 27-inch with faster processor, and use the two of them in tandem. I’m toying with the idea of using the older machine as a Compressor processing station, which might work well or might run into version problems. Worth a try, as I’m generating enough minutes of 720p video every week to make a difference.
The current “see ya” list on a new machine would be the Adobe CS6 suite (which improbably still runs well under High Sierra), a few utilities, and some cruft that has come along from as far back as when OS X was introduced and I was running the whole thing on a Blue Dalmatian iMac that came forward from classic Mac days.
I appreciate the help @ace !