Also the dependency described in Gentoo Wiki seems like a typo. Reproducible: Didn't try
Created attachment 902117 [details] screenshopt of wiki page
In the screenshot, the dependency is described to be 'sys-fs/systemd', which isn't a valid package (at least for now. maybe it was a real package back then?). However, in case it is a typo, I do have 'sys-apps/systemd' installed. I wonder if this module is shipped by the upstream or by Gentoo? I couldn't find a list of upstream dracut modules.
Seems after installing, 90systemd-cryptsetup appeared. However the wiki page still needs a fix.
I't a wiki, just edit the page.