I use LineageOS for microG [1] and I'm planning to move to GrapheneOS once the Pixel 6 gets released (since it finally has guaranteed 5 years of kernel updates).
LineageOS is superb for getting rid of stock OS bloatware and spyware and I have an experience on it that's better than stock Android. However it doesn't have hardened security like GrapheneOS, which is why I want to move to that later. On the other hand microG is needed for push notifications and maps APIs, which GrapheneOS doesn't support so I'm not sure how the fallback options of some of my currently used apps will fare on it.
If microG turns out to be necessary for my workflow then I'll get CalyxOS instead, since it includes microG and is somewhere between LineageOS and GrapheneOS in terms of security.