Here is a comparison of all the various privacy ROMs (and “stock” Android), last updated on June 9 this year.

The person in that other thread who said “iodéOS is a carbon copy of LineageOS” is incorrect. iodéOS comes with a suite of FOSS apps (picked by the community) as optional installs, which is designed to make the transition easier for someone who is brand new to deGoogled Android (similar philosophy to CalyxOS). iodéOS also removes more of the Google services left in LineageOS, such as those associated with the Trust feature, and replaces them with more private alternatives. Additionally, iodéOS has developed a GSI version alongside its officially supported custom device ROMs, which means you can theoretically install and run iodéOS on any currently unsupported device that supports Project Treble.

Graphene is likely to run into issues soon. They were relying on the AOSP source tree including Pixel-specific files. Google isn’t releasing those anymore, so GrapheneOS would have to reverse engineer or extract the needed files somehow.

That’s true for LineageOS, etc too, but they have more releases on non-Pixel phones so they may weather the storm better.

Of course, if you bought a Fairphone, my impression is that these problems go away. It’s just a matter of their policies. I’m a huge fan of the idea of their phones but I don’t own one.

Its not mentioned but I prefer Calyx. Its got better networking features (being able to share your VPN over hotspot and between profiles is a big one for me), and I prefer MicroG (FLOSS) over Sandboxed Play Services (Proprietary). + The calyx devs are generally just really pleasant to talk to. Calyx works on Pixels, Fairphones, a few Motos and sometimes other devices if they can have their bootloader relocked.

Well I’d use grapene if it was available to more than just pixel phones