Hi Neil, I have self-published two books via Amazon KDP. I tried the traditional route first with no success and decided to go it alone. I do enjoy the control you have over your product but it's hard work marketing and trying to drive up sales. You have to have a social media presence and I am doing something every day to market. My third book is due out in the next couple of weeks and I haven't even tried to pitch it. Just went straight to self-pub.
Obviously if making money is the objective then self-publishing is unlikely to make you a millionaire unless you are really lucky.
Good luck with whatever you decide to do. Caroline