High-end GPU is needed ONLY if you “Game in 4K”. Otherwise, even a modern integrated GPU is enough to “drive” a monitor at 4K.
Hence, go ahead and buy a 4K monitor.
A practical advice: There’s hardly any perceptive difference between 2K and 4K resolution in daily workloads.
There’s a massive difference going from 720p to 1080p and from 1080p to 2K. However, beyond that, it is highly subjective.
Regardless, 4K monitors are an investment worth making.