Instead, I installed CalyxOS and have been using it over a year now and I'm very happy with it. Check it out.
You have to be aware that you give that person root when you use Graphene. All possible technical improvements aside this is a very big risk. He claimed he would step back after the video released, then called that a lie and continued with everything.
Calyx seems to be the best alternative right now without such a risk factor.
While I don't think the developers necessarily hallucinates being attacked (i.e. given the nature of the project, I would expect them to be persons of interest, be it from surveillance agencies, or even state actors), the main issue with Rossmann is their claim that he is either personally directing harassment against GOS, or colluding with and encouraging other communities to harass (mainly Kiwifarms, Techlore, CalyxOS, and other Android related FOSS projects). This claim seems to originate then cascade from Rossmann leaving the comment "Informative, but unfortunate" on TechLore's video criticizing GOS's leadership. This is taken as explicit support of TechLore community's / KiwiFarms alleged harrassement on the lead GOS developer, and this has somehow been cascaded and blown out of proportions, and considered by GOS developers as evidence of Rossmann's wrong doing against them.
As mentioned somewhere else, I am using GrapheneOS since 2 or 3 years now, based on Rossmann recommendations. The software is very good, pretty much native Android experience, but without the extra alleged Google snooping / root access. Rossmann himself seemed to have stopped using it as his main device because of fear of retaliation given that the GOS devs could potentially target him. Better safe than sorry. I still use it because I am not that high profile of a person, and generally will use throwaway when it comes to discussing anything GOS related at this point. The overall leadership however, based on Rossmann's and later my personal interactions with them however, did leave a bad after taste.