What refresh rate can an iPad Air (4th gen) output to an external monitor? I see that the specs say it can output to 4K at 30Hz, but what about 1440p?

Question

I've been tasked with finding a suitable monitor for an iPad Air 4th generation.

The official specs say that the iPad can output at 4K/30 Hz. I find the idea of using 30 Hz a bit unfortunate, and I was hoping that perhaps the iPad can output at 60 Hz if equipped with a 1440p monitor.

Thus, what refresh rate can an iPad Air (4th gen) output to an external monitor for the different possible resolutions?