This could actually work. According to Spotify's own data, rock and metal fans are among the most loyal listeners, and the genre seems to outrank pop in global popularity [1]. A significant number of their all-time most-played tracks fall into this category.
I’ve also noticed that many metal fans still buy physical media, often just to support the artists without ever putting into a player (I do this too). I’m not sure if there are solid stats on this, but at least here in Germany, even less mainstream metal bands have frequently hit No. 1 on national album charts in recent years.
Metal fans are definitely committed to their genre and might be open to a dedicated service - especially if offers fair compensation to artists in a credible way.
[1] https://eddietrunk.com/spotify-stats-show-that-heavy-metal-i...
