I'm really glad that Spotify finally allowed us to change our display names, but unfortunately that doesn't solve half the problem. It's difficult, if not impossible, to look up friends or their playlist page via the search engine because the search engine doesn't pull up their display names. I've tried to find friends, even those already on my friends list, by their display names with no luck. I believe that this should be rectified to streamline the social aspect of Spotify.
Improve the search engine, and have a filtered search specifically for other users.
While I think it's odd that we can't change our core username at sign-up, perhaps a separate ID or tag system could be implemented to help people look each other up, because I know seeing a 1,000 duplicate "Bob" display names can be tedious to sift through.
So, for example, each account gets assigned a random 4-number hashtag identifier at the end of their display names (similar to Discord), to help filter out duplicates. Ex: Your friend changes his display name from "[insert long series of numbers here]" to "Bob." But when you look him up, he'll be telling you to look up his name followed by his 4-digit identifier, Bob#1234.
I'm interested in hearing what others in the community and developers have to say. Sorry if this suggestion ends up being redundant, but this social feature being so underdeveloped compared to the rest of what Spotify offers is peculiar to me.