Physics isn't very kind to all these gravity-energy-storage ideas. You need very large objects and substantial height differences to store any meaningful amount of energy. While many ideas about new types of gravity-energy-storage are flaoting around, pumped hydro is the only gravity-storage technology that ever worked in practice.

And even pumped hydro isn't in a great spot. Batteries are essentially competing for the same market (intra-day storage, few hours, high round-trip efficiency), and improving fast.