The idea of seperating the template from the main engine file can be seen here.

Using AI, I generated another tempate file that renders the same grid and images from the engine to 3d. You can unzip and check these.

It uses the same data that the original template uses.

I have uploaded demos in a temp hosting provider : https://real-owl.static.domains/demo3d-4004xmas  and https://real-owl.static.domains/demo3d-4004chessok . The map is the same as (Demo3-ChessAdventure1.html )  https://html-classic.itch.zone/html/13439238/Demo3-ChessAdventure1.html

There are many bugs/issues and I don't know If it worth bothering making a good 3d implementation.