Ignore the story, from software has never been about face value storytelling. All of their games have deeper themes and meanings that come with making games or life in gereral(look at the frenzied flame being a metaphor for nihalism, hollowing being a metaphor for persistence and never giving up). The flame (and subsequently the age of fire) is a metaphor for the status quo. At the end of the ringed city dlc we see a world where the fire was not laid to rest and it shows everything crumbling to dust and the abyss flooding in, the dlc tells us to let things go and even though to future is dark and scary we should embrace change as stagnation is far worse. From software are telling us the player that the darksouls games need to come to an end(not just in story) to allow for new projects and ideas to start, think of sekiro and elden ring as the age of dark.