The iGPU can do DP 1.2, which is enough for a maximum of 5120x2160@30Hz. And the monitor must be connected to the Thunderbolt port. DP 1.4 is only supported from the next higher Intel 11th gen CPU, which then supports up to 8K.
30Hz is usually sufficient for office use, it may be jerky when scrolling, but it is definitely unsuitable for gaming.
60Hz would be ideal.