I have been using Graphene for about 5 years, first on a 4a which was great and now on a 6a which is a bit crap tbh. The software is solid; it’s the harware which is lacking. Much as I love Graphene, I’m having serious doubts about upgrading to a newer Pixel when this one becomes EOL. My partner has a 6 on stock software and she complains about that too. On another note I recently installed e/OS on an old Samsung S7 Edge and I’m really happy with it. It’s given a pretty old phone a new lease of life, increased the battery life etc. You can check if your phone is compatible here
e/OS