I’m an experienced technologist (a software engineer for over 30 years), I used to regularly install CyanogenMod on my phones. While I didn’t find the graphene OS installation to be particularly difficult, I did find actually using it to be too much of a challenge to live with every day. The biggest single problem I can recall is that I could not do any group SMS texts. Many searches and attempts at fixes later, I realized that it was a known bug that for reasons unknown did not seem to affect all users. There were a number of minor annoyances in addition to that bug.

That may reflect more on how Google has locked down things on the pixel phones, or other stuff they’ve done to keep things as proprietary as possible in their software and devices. I switched back because it wasn’t worth the hassle to me.