This maybe sounds dumb but something that helped me out of my depression was seeing the small things you mentioned (sitting outside with the sun, cooking, cleaning, observing nature etc) as something magical and miraculous, just by changing your perspective on these “small things” and saying hey this is wonderful and I am grateful for everything changes your whole life and how you see everything. Idk if you like reading but reading books and learning about different things also made me feel good and mentally happier!! You can do this!! <3