I have my cd (and vinyl) music collection backed up on the secondary computer hard drive (the main pc hard drive has the operating system and software on - the secondary drive has the files - music, pics, videos, documents etc).

There’s also a backup of the music on an another external hard drive stored in a drawer elsewhere (just in case of theft, damage, hd failure etc) - and I also use Google Play - which is very easy to use - and can be accessed on any near enough any modern phone, tablet, pc or mac device with an internet connection when out and about 😃)

I think Google Play still comes free when you sign up for a gmail account (if you haven’t already got one) - and it’s nice to be able to play a rare song or two from a band to a mate who expressed an interest in them etc - without too much hassle.

That B2 looks an impressive bit of kit mate - though if you already have a quality Sonos set-up it may be a little superfluous? (depending on your set-up / requirements, of course)