Well there is no ‘one’ spirit that can help your band become successful, you would need to contact a range of spirits that can each help you with a part of the goal that leads to success. Like one spirit may inspire you to make better music overall, the other spirits may inspire others to find and listen to your band, while another spirit may convince most that listen that your band is awesome and worthwhile even people that wouldn’t seem to be interested in your kind of music based on their personalities and appearance.
Bune is good for helping with large sums of money and is good for those that maybe need an extra $1,300 for a down payment on a car, or to inspire a landlord to offer a cheaper than usual rate on an apartment. But I have heard others say that it was either Bethor or Beleth, I forgot which one as I have not worked with either of them yet. that is best for long term sources of conitinual money in smaller more normal amounts. Now I know Amaymon is good for business successes as he helped me chase away a douche bag that was dead set on ruining my businesses good name simply because I also offer metaphysical items and he was an atheist troll. And not only were the proper sources to handle the situation sent to me and the guy disappeared without a trace, but I also had a rush of new orders for a few weeks after that as an added bonus.
He might be able to inspire some creativity for PA that can attract people to your band. But you have to work with multiple demons to make that a reality. Trust me, Lucifer himself wouldn’t even take on something like that, he is one of the ones who adds to the puzzle for success so he does help but he wants you to work for your success so he only helps with bits and pieces. Now, I’m sure there are some ancient gods that if the right sacrifice was made, they could make this all happen for you and unfold very quickly but they may require human sacrifice or something brutal.
We know when the stars say they sold their soul, some of them are just saying that for attention but others are not and are in deed practicing magick, and some of those people in Hollywood I would not put it past them to have actually murdered someone to make that happen, because those people are already living gods in their attitude and self-love abilities before they become living gods on stage or on screen amongst others.