This is just me playing around so whether it can be adapted to work with your scenario I am not sure. The basic idea is to use a cylinder for the sky. I have done it with limits on the up and down movements on the camera but could be changed for other cameras.
This Babylon.js Playground uses the px, nz, nx, pz skybox images to form one long image.
This https://www.babylonjs-playground.com/#SEPRT4#1 uses a square image (adapted to tile left to right)
To get things as you want you will probably need to improve: images, image ratio, pixelation, lighting, positioning of cylinder and/or camera.
Hopefully you might get some ideas from this.