You don't want a video wall, you want a quad processor, or a multiplexor.

A video wall is made up of multiple TVs to create one large image.

A quad takes up to four individual inputs and shows them on a single screen.

I am not sure who would have them in a version that supports 4K video at 60 frames per second, but they definitely have 1080p versions at a reasonable price.

Like this: https://www.amazon.com/gofanco-Prophecy-Multi-Viewer-Extractor-PRO-QuadView/dp/B07SQGD95C/ref=sr_1_17_sspa