Now, don’t get me wrong, I like the premise of GrapheneOS. The security features it offers are great. However, you’re sacrificing useful hardware features by using it.
Currently, the only phones that support GrapheneOS are Pixels, which lack the microSD card slot, dual sims, and a HEADPHONE JACK! To me, those features are not worth sacrificing for a little extra privacy.
Compared to LineageOS, however, they support a broad range of devices, even pixels. I can look through their supported devices and find one that has a headphone jack, microSD card slot, dual sims, etc. Yes, it’s less private than GrapheneOS, but it’s still more private than stock android or any of those other OEM roms (OneUI for example).
You can still keep some privacy using LineageOS while preserving functionality with projects like MicroG.
Overall, I think for the time being, unless you are really paranoid or live in a anti-privacy area, LineageOS is the better OS to use than GrapheneOS due to still gaining some level of privacy while preserving useful hardware festures. Once GrapheneOS branches out from Pixel phones, I might change my opinion.
You’re not wrong, as there are conscious tradeoffs being made. By limiting GrapheneOS to a specific phone family, it can tighten security. In contrast, LineageOS has to manage issues across a wider range of devices, which limits what it can do. FWIW, GrapheneOS is going to partner with an OEM manufacturer, so I wouldn’t expect it to ever become available for a broad array of devices.