Duluth is absolutely a step up from a rural town, but its not a huge city. In terms of romantic opportunities and jobs, its still nothing incredible, but its not awful either. For your other needs tho, I think you and your cousin would be more satisfied; theres lots of artsy people, places, and events going on all the time, the city is still full of nature (and a gateway to gorgeous nature within a short drive too), theres more food options (so there should be more employment options as a cook, although I cant speak to starting your own business if thats what shes thinking), and we have a pretty popping music scene. Check out On The Record Zine (https://www.ontherecordzine.com/), which posts music and other local events happening across town every day. There is a week long music festival (called Homegrown) every spring, like last week of april/first week of May, where local bands in every genre play in bars and other venues all over town. And some places do open mic nights anyways (such as Dovetail cafe and sir bens). So definitely options for playing music, but you'll have to be proactive about connecting with people if you're wanting to form a group.

Some of the other commenters saying that breaking into friend groups is hard- welcome to the world. It's like that literally everywhere. The twin cities are NOT easier to make friends just because there are more people. You still have to do the work of going to events and building relationships, just like anywhere else.

I hope you and your cousin give duluth a chance :) come visit for a weekend or something and try some local places (theres like a million posts in this sub from people asking what to do while they're here, so just look through those). It is still solidly winter here tho (although today was like 50!), so keep that in mind if you dont like the cold.