It used four synchronized PCs with a total cost of ~$20,000 to render three 4K panels, which is pocket change for a large production. The LED walls or a single lens costs more than that!

This goes into way more technical details: https://ascmag.com/articles/the-Mandalorian Particularly interesting is how the system had ~10 frames of latency, so excessively fast camera turns would show lower quality renders.