You can turn off the shutter sound just fine. This can even be done on Japanese Pixels.

https://discuss.grapheneos.org/d/7649-camera-shutter-sound-on-pixel-6a-jp-version

In addition to GPay contactless, Android Auto will also not work on GrapheneOS.

Huh? It has a dark mode in Settings->Theme.

As for ad-blocking, I have found that system-wide blocking works great as suggested in the docs https://grapheneos.org/faq#ad-blocking. YMMV…

Cromite indeed looks great.

This may not be helpful, but if you’re willing to flash GrapheneOS on a pixel, Vanadium is wonderful.

Bromite has been abandoned. https://github.com/bromite/bromite/issues/2641

Ungoogled chromium binaries are built by anyone so don’t get them from there. https://github.com/ungoogled-software/ungoogled-chromium#third-party-binaries