I could write a novella on this...so many thoughts!
But firstly, I agree that a baseline for happiness requires that our most basic needs are met - food, health and shelter. Without these it's very tough to get out of desperation.

Given this, then next are the also basic needs of love, community and meaningful purpose in life and this is where contemporary life falls short. We think that finding the love of our lives will give us that happiness we've always wanted, that the perfect job will fill the void, and if we just had a better family etc..., but I believe that this misses the point. In order for any of these things to bring happiness, our relationship within ourselves must be alive, growing, healthy and resilient. Then yes we can love more freely and fully, give more fully to our life purpose, and enjoy liife more!

Lastly, happiness is usually defined as a feeling, but I think it's an action (not passive). We create happiness via engagement with ourselves and our lives!

Anyway, today that's my thinking but it's always a work in progress!
ps. my family is Danish and I have always been suspect of all the happiness research about Denmark. Danes are bouyant and chipper but that's not the same thing as happiness if you know what i mean and I suspect you do given what you've said here, but that's another conversation.
Thanks for the thought provoking post!