> Hopefully QNAP is charting a path to allow their users to migrate from their fork to OpenZFS

This kind of migration is the stuff of nightmares. The main job of a NAS is to keep the data safe. A file system migration that works in every one of those corner cases present in the wild is statistically unlikely. The kind of bad publicity this can bring is what can sink a company. The only way I'd ever do this is by starting fresh on different storage and replicating the data.