I’m going to add something else to the mix. Online backing up. Seeing as I don’t have the n.a.s yet or the drives would it be easier? I can imagine a n.a.s would be cheaper and more storage in the long run. Also I have no prior knowledge how to set up a n.a.s, I’ve heard the synology’s are pretty user friendly.
Setting up NAS is pretty easy, there is usually a setup prog which'll find the NAS on your network, if not enter in the IP then you have the wizard screen, you'll need the downloaded firmware file during setup.
Username, rights etc, what apps you want, creating RAID type, music location and indexing etc.
I use a pi so had to create user for the pi, NFS user right access etc. It's as complicated as you need it to be. Used to have LMS installed but got rid of that, now it's just a NAS for music, video, software backup.
If you want to use docker you'll need an intel based NAS. Mines realtek so can't install it, but it's plenty fast, quad core 2ghz or something like that. 2GB RAM, not upgradeable but 2GB is plenty for my use.
I would recommend at least a dual bay. Mines a quad bay, using two of the four.