OP says 18 months and Gust was waiting for annual bonuses and stock to mature. As you say, you chose to coast at your own job as a reasonable and fair response

OP says 18 months and Gust was waiting for annual bonuses and stock to mature. As you say, you chose to coast at your own job as a reasonable and fair response. You did the work you were contracted to do and got paid correspondingly. Yeah you’d have liked a promotion path to a more demanding and rewarding role, but that’s just not something your employeer needed/wanted. Lots of jobs aren’t our perfect dream jobs. But I assume you started looking in the meantime, and when you did find a job which better fit your ambitions you moved on, and did so in a professional manner which ensures your own professional reputation stays intact. Gust just burnt the world; took his own pain and paid it forward. Victim (partly self-made) becomes an abuser himself. Sorry, no, I’m going to call that.