@leon -- Those look equivalent to the steps I took. I just used the router GUI's jffs backup/restore option, but your tar options should do the same job. It sure seemed to fix the problem for me. I had been seeing the problem recur within a week (sometimes within a couple days) of reboot, and after the backup/format/restore it ran for 3-4 weeks without any further problem.
My fix verification is limited to that 3-4 weeks because that's when I replaced that router and my old AP with a pair of AX86U's.
My fix verification is limited to that 3-4 weeks because that's when I replaced that router and my old AP with a pair of AX86U's.