I bought Pixel 7a and flashed GrapheneOS and running it without a single Google app. My experience has been pretty good so far.
I've used custom ROMs for years, but never used Graphene.
My current phone is a Xiaomi Mi9T. With a custom ROM, to properly make use of the camera you need to flash a magisk module. Otherwise you are stuck with the stock android camera app which doesn't perform nearly as well.
This phone is on its last legs, the screen was smashed so I had to replace it with a cheaper LCD, which has affected battery life and sometimes is unresponsive.
Thinking about getting a used Pixel 6 and giving Graphene a go.
> Google Camera can take full advantage of the available cameras and image processing hardware as it can on the stock OS and does not require GSF or sandboxed Google Play on GrapheneOS. Direct TPU and GXP access by Google apps including Google Camera is controlled by a toggle added by GrapheneOS and doesn't provide them with any additional access to data. The toggle exists for attack surface reduction. Every app can use the TPU and GXP via standard APIs including the Android Neural Networks API and Camera2 API regardless.
> We aim to reduce the benefits of Google Camera compared to GrapheneOS Camera over time, especially on Pixels. Many features of Google Camera will end up being available for GrapheneOS Camera in the next year or so via CameraX extensions including more aggressive HDR+, Night Sight and Portrait. Video features such as slow motion and time lapse are likely further away than within the next year. These video features could potentially be provided via CameraX vendor extensions or could be implemented via our own post-processing of the video output. Panorama, Photo Sphere, Astrophotography, Motion Photos, Frequent Faces, Dual Exposure Controls, Google Lens, etc. aren't on the roadmap for GrapheneOS Camera. Video frame rate configuration and H.265 support should be available for GrapheneOS Camera in the near future via CameraX improvements along with DNG (RAW) support in the further future.
All the info: https://grapheneos.org/usage#camera