When I’m unhappy, I feel like I’m doing life wrong. I’d rather be happy. But is happiness the point of life, or is there more to it? If I pursue happiness, mine first then for those around me, is that selfish? But if there’s a bigger purpose, then what about people with Alzheimer’s or dementia who can’t recall recent experiences or make plans?
I urge you to look into Buddhism. Not as a religion to do ritualistic shit but as a philosophy, as Buddha intended. The only purpose of Buddhism is to address what you're feeling right now.
You might be surprised to hear that I've explored Buddhism somewhat, and I think it has helped. I went from worrying that I'm not good enough and I'm not achieving enough, to just accepting who and what I am. I feel that's been positive. The video you linked sums it up nicely. I enjoy the book Who ordered this truckload of dung? : inspiring stories for welcoming life's difficulties by Ajahn Brahm (https://archive.org/details/whoorderedthistr0000ajah).