I have run out of bookshelf space

For someone like me with no prospects for the future, buying books is the only promise I make in life. Visiting bookstores, being drawn to the covers and titles of the books I encounter, and purchasing them to line up on my bookshelf at home is nothing less than a promise to those books that I will read them someday. In a life that feels aimless and unreliable, the existence of the certainty that "I will read this book someday" serves as a modest support for me right now.
Currently, I have about 120 unread books on my bookshelf at home, and since my reading speed cannot keep up with my buying speed, the number of unread books increases daily and continues to crowd my home storage, so I do not know if I will be able to finish reading all the books I have bought in my lifetime. However, in a life that could end at any time, what is the point of considering such things? Even if I had plans to hang out with a friend tomorrow, there is a possibility that I could die for some reason tonight and be unable to keep that promise. Who could blame that as a breach of faith? Even if there are books I cannot read in this world, it simply means that I reached the end of my lifespan before I could read them. Since I cannot decide the time of my death myself, there is legitimacy in my continuing to buy books.
As I gaze at the spines of the unread books lined up on my shelf like that, I feel that stacking books definitely enriches the reading experience. I buy books and leave them unread. I often read newly bought books with the same momentum, so when I choose a book to read, the ones that have been stacked for a long time are not often picked up. However, the day those books are read arrives suddenly. The day when a book that has been stacked unread for five or ten years becomes necessary arrives without me even expecting it. What is interesting at such times is that the "me" who was interested in the book and bought it, and the "me" who has now picked it up to read it, are already different people. It is the sensation of the past when I bought it and the present when I try to read it being connected by a single line. In between, there is the time when the book was stacked without being opened. I think that cherishing the "me" who was initially interested, the time spent not reading it, and the "me" who now wants to read it and has some thoughts about it, is all part of the reading experience.
Well, as I go about my days buying, reading, buying, and reading books like that, for some time now, I have been in a state where I lack the mental stamina to digest heavy books. I like novels that seem to have extracted only love and kindness from the world. I am also interested in entertainment novels like mysteries that I can enjoy while keeping a distance from negative emotions. Consequently, the area of my bookshelf containing unread books inevitably accumulates gloomy novels that require mental capacity and a large amount of energy to read, and specialized books that discuss the reality I hate, and their concentration increases day by day. Perhaps my own anxiety and melancholy are reflected in the unread books. Although they are books I cannot read right now, they will be necessary for some future version of me. I intend to keep buying heavy books until the day they break through the floor of my apartment.