I always wait, and it crashes eventually if that option is marked. It wasn't happening on older maps with that option on. Specifically it is De Dust 2, released on 2020 10th of June. It worked fine with De Mirage, and I will need to do this on De Train as well.
I tried adding all extracted models (with their sub folders) to Counter-Strike Global Offensive\csgo\models and changed to this directory in WallWorm settings too. After import, models appear as yellow squares on this map anyway.
I'll keep investigating, maybe I am doing something wrong.