August 2024 update
I finally filled up the primary storage server with 1450 plots. My next task is to replace the couple of Pi4's that have a pair of external hard disks with the Qnap TR-004 (4 bay) storage units. To that end I have ordered a couple of Pi5 (8GB). I will start by swapping one at a time so that I have as may plots online at a time. Each of the Pi4's have around 275 plots so I should be able to double that. My concern is the TR-004 connected to a Pi5 will be slow as the Pi only has USB 3.0 (5 Gbit) ports even though the TR-004 supports USB 3.2 gen 2 (10 Gbit) connections. I guess I will find out. If it works out one could scale the solution to have multiple Pi5/TR-004 running as a harvester only requiring two power points and 1 network connection each.