libGDX is based on OpenGL (ES), but iOS 12 has officially deprecated OpenGL. There will be tons of job to do if libGDX wants to evolve. For commercial engines, they have started long to adapt to the OpenGL deprecation. Any plan from libGDX team? Or have they already started the works?
Initially they were reluctant to support Vulkan. Recently they are looking into both of Metal and Vulkan support by using ANGLE as backend.
Metal/Vulkan Support [Planned]
We are well aware that Apple has deprecated OpenGL (ES) on iOS and macOS. Thus, we are looking into Metal/Vulkan support in the near future. Projects like ANGLE look very promising for this.
See their roadmap.
Currently, ANGLE's Metal support is still in progress. Once it has done, the libGDX developer team will work on. I hope so.