I was reading some of the latest post from the Sultan Kernel thread in XDA, and as far as my understanding goes, it is possible to install this custom Kernel in custom ROMs.
Is it possible to install it with Graphene OS? Has anyone tried it? Would there be any difference?

    I think this is a terrible idea. Installing a third-party kernel as a minimum will probably break some GrapheneOS features (full USB-C disconnection) or quite possibly the system will be completely broken.
    Not to mention the security and lack of patches from GrapheneOS

    tronchoti Why would you want to do this with GrapheneOS in the first place?

      1fexd I'm not really planning on doing it. I was just wondering since I came across that post yesterday while reading about Pixel 8 Pro and ROMs.
      I just got a new Pixel 8 Pro. Graphene OS will be installed in a few days😄

      Not sure their changes would be compatible with GrapheneOS. GrapheneOS makes some changes to the kernel for further hardening, etc. You can see what's been done with the kernel on the releases page on the website: https://grapheneos.org/releases#changelog

      Also, the project wrote this thread the other day: https://grapheneos.social/@GrapheneOS/113961075324902277. This part might be of interest:

      We started deploying RANDSTRUCT for the kernel, which will eventually be used to have multiple possible struct memory layouts for each device model chosen randomly at boot. Our work on reducing kernel attack surface also continued.

      We plan to focus more on Linux kernel security going forward.

      As you can see, the kernel isn't neglected by GrapheneOS developers. I don't think it would be wise to use another kernel.

      tronchoti GrapheneOS provides a hardened kernel with protection from kernel exploits and features used in the rest of the OS. The rest of the OS depends on it. You also can't replace components of the OS with other things without losing verified boot and updates since you'd need to leave it unlocked. There are multiple reasons you can't use it.