Samsung didn't include any bloatware, Spotify is the most used Music streaming App, and they have a partnership with Samsung so it's extremely expected for them to pre-install the App plus offering 6 months of Premium Membership.
I'm using the general definition of bloatware. You're using the definition of only unwanted (and useless?) software as bloatware. Both definitions are correct.
I really don't have any issue with Samsung including Spotify. It's useful to many people. It's still bloatware though.
Using your definition, if I purchased an S10, I'd remove Spotify because I don't use it. For me, it would be useless and a waste of space. Therefore it's bloatware to me according to your definition and is bloatware using the broader definition I use for bloatware. According to either definition, it's bloatware for me but not bloatware to you using your definition (but is with my broader one).