Been offered a funded PhD at a good UK university.

It's a PhD combining Machine Learning (a branch of AI) and Engineering. I currently earn £28k in my graduate engineer job but I don't enjoy what I do and I'm interested in the PhD.

I think I can leverage this PhD into a far more interesting/more rewarding (economically) career. What do you think? And what do you think the effect on my SMV would be?

I'm a 22y/o man with no kids.