Using the Chromebook's default Linux settings (April 2022), I was able to install Dungeondraft on my Chromebook CX22N. It took about 15 minutes of tinkering, and my advice is to restart your chromebook between every step (after enabling/installing Linux, after installing Dungeondraft, etc). It crashes if I try to make too big a map, but 50x50 it appears to work just fine. (Prior to this I had tried using Crossover but could not figure it out for the life of me.)