As you may know, I like trying out alternative operating systems. I bought a Pixel 6 device and installed GrapheneOS on it. The web installer instructions are pretty easy to follow, and I was able to do it in less than an hour. It took longer to do the Android updates it recommends doing before installing GrapheneOS.
The initial screen is bare. If you just needed to do messaging and calls, it would get the job done. It is possible to install a sandboxed version of Google Play. It works pretty much the same, although I found that some apps that rely on the wifi network or cross-app verification do not work. For example, Nextcloud Notes can not be used with the Nextcloud app authentication because of the sandboxing. The same is also true of apps like Orbi, Sonos, et al that cannot access what they need outside the sandbox. So, I’m either not using these apps or using alternatives.
It also flashes when booting that the operating system has changed, but it doesn’t present a problem. You just have to wait a few more seconds for the phone to boot.
Overall, if you need a flawless experience. I’d stick with the stock OS. If you can deal with a few things not working for better security, or at least worth trying it out, you might want to consider trying it. It is possible to go back to the stock OS later, and it could provide a useful learning experience.