Have you tired volunteering with any of the climate friendly pick-up-trash and plant-a-tree type of organizations near you? It can make a massive difference to your mental health. Yeah, it’s not enough, but it puts you from the side of “we’re all going to die” to “we need to do more as a species, but I’m doing my part.” It will also help you get outside and meet people. I also recommend a bit of gardening, if you like it.