So, it turns out one of my drives are failing and I need to send it for RMA.
My problem is that after having removed the drive from the system, having first copied all the data to a different drive in the SnapRAID, 1. SnapRAID is refusing to behave 2. even though I deleted the drive in the OMV GUI, SnapRAID says the drive is missing and I can't sync which leads to 3. my data is inaccessible, despite being on the drives.
I removed the hard drive both in the SnapRAID UI and unders Disks. So what am I supposed to do now to make it all work again, as there are no explanations on how to actually remove a drive in the SnapRAID manual, it just tells you how to replace one. Does this mean my NAS is out of commission until my replacement drive arrives? If so, then SnapRAID is mostly pointless, as it caused more headache than it's supposed to solve.