I don't have an answer more a question. In my case I have 11.9TB duplicated and 5.1TB other.
Could you detail a little more about dealing with previous versions.
Would this be done from the pooled drive or the individual spinner?
Today, I realized you had newer versions of DP so I just manually updated to 2.3.1.1448 from 2.2.5.1237. Automatic updates had not worked.
Also, I added 2 -2TB NVME M2 drives and set rebalance to 3 copies - strange thing is, the M2's seem to be ignored so far.