erja I will revert back to Stock OS and sell the phone.
Okay. If you want a secure phone, an iPhone is a good choice.
erja Graphene Os seems to me to be in a constant Beta release
It isn't. GrapheneOS is based on AOSP, and GrapheneOS is always up to date with the latest upstream releases. The developers put in a lot of time and work to make sure GrapheneOS-specific features are tested and are ready for GrapheneOS users. That said, there are a number of upstream bugs that GrapheneOS has to fix. In many cases, bugs can affect the stock OS as well.
erja There are also many security issues Graphene depends on Google to solve.
This makes sense because AOSP is developed by Google.
erja Graphene them selves brags about that their os is the most secure Os ther is. I doubt that.
GrapheneOS is objectively more secure, mostly because of the reasons listed in this section of the website: https://grapheneos.org/features#exploit-protection. AOSP is already very secure, but GrapheneOS makes AOSP even more secure
Anyway, if GrapheneOS didn't work out for you, then that's okay. Here are instructions on how to install the stock OS: https://grapheneos.org/install/web#replacing-grapheneos-with-the-stock-os