I can't say that money and happiness are unrelated in any way. They are quite related. Because having no money or a really few amount of money equals to being unhappy to me. Maybe this is different for many people also. But I can't be content about my life unless I have enough money to be able to get something I like. I don't mean that I must be a really rich person. I mean that I should be able to afford the things I like.
We feel much more confident and calm if we have enough money to live on. After all, we live in this rough physical world and are obliged, at a minimum, to maintain our body, as well as take care of people close to us. Therefore, we can say that money is an integral part of our happiness. But this is not always a prerequisite, just as a person can be unhappy even with a large amount of money. Life is diverse and multifaceted, and there are a lot of specific situations in it that are intertwined and form an infinite number of options.