How much I was confused with the original version of the backrooms, but in fact everything was very simple, all I had to do was create a grid of lines, and say, remove 60% of random segments of line fragments, and draw walls along these lines, and that’s it! It turns out to be very effective and easy to create any endless maze.
The rest of the maps from the lines can be viewed in my 3 version from the theme → Makarov retopology - Demos and projects - Babylon.js