In this case, when your style changes to suit others and increase your popularity, that's pretty much the epitome of selling out. Taking a new job to advance your career is called advancing your career.
(Based on a true story.) I worked for myself and sold my thing. When bossman hired me to design for him, I was hired to do what he wanted. I dug the design, but it was not my design. But I quit working for him because I wanted to go back to working for myself. I sold out to work for bossman when I wasn't doing my own thing.
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