I was a synology user, but reached the drive limit and made the decision to move away at that point.

Built a PC and installed Unraid, it's not free and you can do it all with linux if you're so inclined for free, but I'm lazy and wanted something that would just work without me having to edit configuration files.

It's not built for high performance, but it makes up for that with the way it configures the drives, I have 2 parity drives so can cope with a couple of failures before I lose data, the thing here is that the way the drives are confgured it uses some sort of overlaid FS to combine the space across all the drives. It tries to balance file storage across all the drives.

The neat thing is, that say for example both parity drives failed and then one of the drives in the array failed, then I only lose the data on that drive, not the whole array.