Ran diagnostics. Used Washer Service Manual I found on line. Diagnosis was tedious, but led to a bad component. Clutch (or slider, it is called sometimes) did not engage during spin cycles. Tested the output of the board, 120VAC was going to the magnetic clutch, but it did not move when commanded. The teeth on the slider and the rotor looked ok. Everything moved easily by hand.
Replacing the magnetic clutch is fairly easy. Have towels available. The washer must be tipped up to remove/replace, and the washer will have some water in it. Your video was very helpful.
BTW, the Samsung service manual did not reference replacing the magnetic clutch, but it certainly was the problem.