I have OnePlus 7 Pro that I successfully flashed with LineageOS 21 with MicroG. Do you have some interesting apps or ideas to take advantage of it? I thought of some Magisk modules. Maybe someone is more experience than me! This is the spare smartphone, the main one is GrapheneOS, so I don’t mind breaking stuff.
Read their own official documentation. They officially said they didn’t have anyone responsible for security and it’s not what they cared about. This combined with basically giving the whole system root permission is very bad for security