Mr. .45 ACP….Lumin U1 Mini is a pure streamer. You would need a DAC and going from U1 Mini into your AQ cobalt would be a potential waste of resources.
If you like a one box solution, some of the options include, Lumin D2, HiFi Rose, Ever Solo (see Steve Huff’s review on YouTube), iFi Neo and your aforementioned cheaper option of Bluesound Node among others.
Alternative would be to get a decent DAC, i.e a Chord Qutest and continue using your your macbook but the mac isn’t that good as a streamer. If you’re looking for convenience and don’t want to spend a lot, the Bluesound Node is your ticket