To be a solo financial adviser, do you need to register as an RIA?

I am looking to become a financial planner, fee only, charging by the hour, or flat fees for plans. Is this a viable model? Do I need to be registered as an RIA? I've been in the financial industry my entire career, but on the Product development side. Always hated it. Went through the CFP curriculum, unfortunately failed the exam, but gearing up to taking it exam. I don't really want to deal with investment management (i would only suggest VUG, VOO and VTI anyways :)), but understand that that's where most money is, in AUM fees? Any help is appreciated!