As an added datapoint: I have Roon ROCK on a NUC and my music on a Synology DS1819+.
I control Roon using 2 ipads and an iPhone. To err on the side of caution, I only upgraded 1 iPad (an older iPad Air 2) to iOS 13.5.1. After the upgrade, it connected immediately to the Roon Core and the library. Will upgrade the other i-devices to 13.5.1 next.