Just thought y'all may find Dave Nanian's
discussion /blog re APFS issues of interest.
As I don't understand much of it, I am ill-prepared to comment. Still, I remain sympathetic to others here 'bouts who (also) opine that non-trivial await (including challenges for some developers such as DiskWarrior).
FWIW: I used SD! for years and loved it, but have since switched to Carbon Copy Cloner (and love that even more).