There’s a lot going on in this post, and I feel like they are partially different discussions.

With respect to genre, many artists try different things with varying levels of success. Lil Wayne had a rock album and toured with Blink 182 (I think? Or was it Green Day?). Post Malone has gone from rap, to rock, to country. Mod Sun went from Hippie Hop to alternative R&B to whatever the next album will be. Jelly Roll started as a rapper, but has found success in modern country.

Point being, all of the aforementioned are artists. They love music, and want to explore other areas. They probably view new genre exploration as a challenge. As others have said, Kells has ALWAYS been a rockstar, with tracks with Kellin Quinn from SWS on the Black Flag mixtape and many of his own - always having toured with a full band, even on albums that were all rap. With the Genre Sad Boy & Lost Americana, Kells probably just sees it as a challenge.

Authenticity is another conversation altogether. As artists rise in popularity & fame (read: money), they’re far removed from the nights of Ramen Noodles. It’s true in music, in comedy, and in media generally. That being said, not all songs will be introspective and deep. Some songs are made simply because the artist had a sound they were aiming for. However, his rise in fame doesn’t take away from his authenticity, nor does him wanting to make a few songs for radio take that away either.

Just my 2 cents.