as reported by @mshevchuk, quote:
In Org-roam v2,
org-roam-modeis not longer a minor mode, so doing so makes little sense. Instead, one can put(org-roam-bibtex-mode +1)in the:configsection ofuse-package org-roam:
see: Minimal setup for helm-bibtex, org-roam v2, org-roam-bibtex