A trick I use when DDA become stale is hand-craft a special “scenario” using the debug menu. Pick a location, edit the map as needed, spawn items (weapon, supplies) and zombies (sometimes other things too) and see if I can survive.
The experimental has this too, you can chose a scenario among many, pick a location and try to survive. Also make some goal for yourself. Explore those exotic location, find an artifact, build a death-mobile, become a cyborg, or just try out those delicious mutagen.