rsync -aP, as mentioned in the migration howto.
I could see zero values before, when the rpi4 cpu is at 100% (as currently, running with rsync in parallel, too). the values are correct shown again, as soon as the cpu usage slows down.
my fear is, that rsync is additionally challenging the system, which is already at 100% cpu - as long as the node is online and running. suspension & audit section is completely empty.
The ago of the node is around 4-5 months.
Update : rsync will take 1-2 weeks, when the node is up and running with the SMR HDD.
Update 2: node stopped - rsync will take around 1-2 days