CalyxOS was not a hardened OS and is a much different space from GrapheneOS. https://eylenburg.github.io/android_comparison.htm provides a high quality comparison of the privacy and security between different alternate AOSP-based operating systems.

CalyxOS has essentially been discontinued, see https://calyxos.org/news/2025/08/01/a-letter-to-our-communit.... It hasn't received the 2025-06-05 or later patch level.