An argument can be made that all actions people take are for their own self-interest. Even things like helping the community is done for reciprocal benefits for yourself plus the general increase in respect.
Another point is that if all people just act for their own self-interest, they will have a better life themselves, and if everyone does the same, some sort of proper balance will be achieved.
I have been having some occasional discussions with my friends over this. I personally disagree, but would love to hear what others have to say. Feel free to discuss!
So reading the title I came to say yes with a caveat but you included the caveat. The thing is self interest is ultimately about happiness but humans don’t always understand what brings it. Drug use is sorta the basest level. Chasing literal physcial sensation of pleasure. Sex addiction would be next which is really just chasing drugs that our body naturally makes. Same with danger addiction and such. Then you get to like food addiction. Next is money addicition which is sorta looking at it as a gateway to everything. Recognizing how important others are on different levels means a lot. Its a bit like the hierarchy of needs. You can maybe get physiological on ones own but after that any increase in actual happiness involves having to improve your environment and society and ultimately the earth. So I guess Im saying yes but people can pervert it for not seeing the forest for the trees.