Here are a few factors to consider when deciding whether to boost the agency website page or individual artist pages:

Agency website page: Boosting the overall agency page would help establish your agency's brand and credibility. It shows you have a stable business representing multiple artists. However, it may not directly lead to bookings for specific artists.

Artist pages: Boosting individual artist pages allows you to target fans directly interested in that artist's style, look, music samples, etc. This makes it more likely a boosted post would convert into real bookings, streams, or sales for that artist. However, boosting many artist pages could be more expensive than one agency page boost.

Goals: If your main goal is brand awareness and credibility for the new agency, boost the agency page. If your goal is to generate specific opportunities for your artists, boost the top individual artist pages first to see what performs best.

Budget: Consider your marketing budget; boosting the agency page may have a higher return on investment at first if funds are limited, versus boosting many artist pages.