(((TAS)))
Maybe instead of thinking about whether or not fighting is worth it and the battlefield is for you, you could find a measure relief by considering life through a different set of metaphors? ie life as a journey, a pilgrimage, a process of discovery, a river to float on, a cycle of seasons, something. . . Talking of battlefields expresses one aspect of reality, but focusing on that exclusively and literally (especially when you are feeling depressed) can be exhausting. I just wondered if shaking up your perspective could help a bit, at least for the moment.
Surely there is at least one thing or person that you find inspiring enough (or at least interesting enough) to live for? Maybe try focusing on that? It won't solve everything, but sometimes just a glimmer of hope is enough to help you through the darkest times.
Take care and stay safe. Will be thinking of you.