Sorry for a late reply. The grapheneOS seems to have a problem with not a very welcoming community but their OS is still good with all the security and privacy features that it comes with? If it is not Google Pixel + GrapheneOS that is the most private way of using a mobile phone then what is the most private way? I see this set up recommended in almost every privacy community including this thread.
Yes removing Google Play services will reduce the spying that Google does on you but the mobile company can still possibly spy on you. How do I check that my phone has a randomized MAC address or not?