Take back control!
A sense of genuine scarcity, specialness or rarity. Things that others do not, or cannot have. Items that have a sense of historicity about them. Hidden gems, secrets or banned things that only the collector posesses. Things with their own stories.
Physical collections have this interesting property that they tend to automatically become more unique and interesting over time as they accumulate history and comparable items are destroyed or lost.
Arrangement, curation and the search for completeness within a chosen field can count for a lot. But I posit that hoarding commercially released, widely available digital files cannot really satisfy a true urge to collect. Producing and trading bootlegs is a lot closer.
I suppose NFTs could fill some of the gap here but they seem like simulacra to me.
I've been thinking about writing a Spotify ripper.
OCRemix fan works come to mind, as does anything foreign. I paid 50 (50!) USD for an imported CD of Duke of Pianeet's Singularity.
I still collect things I care about, I have tons of FLACs (some ripped from my CDs, some bought online) from artists that are meaningful to me and whose music is significant in my view.
I'm still grateful for Youtube and Deezer (I hate Spotify's UX so I'm never there) for providing me access to music I wouldn't necessarily collect, but I'm now also not at will of some radio DJ when I want that kind of ephemeral music in my life.