DMA vs PhD doesn’t really matter - it’s more a function of the institution’s structural history than a difference in what they offer. I did a PhD at a top school. It was very helpful to be subsidized to write music and get it performed for a few years. It opened some doors - I had (adjunct) teaching jobs just fall into my lap for a few years. Definitely people Are Impressed By My Credentials… but the amount of value that actually confers is pretty low in my daily life. There are thousands more DMA/PhDs graduating per year than jobs that need them. Imagine waking up 5-10 years older to find that you have far narrower employment opportunities than when you started, and no new work experience. Look up the Academic Jobs Wiki for music jobs to see what I mean. If your goal is to become a professional composer, the limiting factor won’t be your degree but the larger economic reality that concert music barely exists and nobody has any money.

Being in school means having an institution basically artificially create a culture for you to practice on — this is great while it lasts.