I have read a bit of the report and I barely understand the details it explains (I’m not an Android expert). So I would appreciate if someone can “translate” whether any of that technical details apply to Fairphone OS.
The preinstalled software on the FPOS is rather limited. It includes Google and Qualcomm components, some apps developed by Fairphone themselves such as the updater and the iFixit app. There is no software from mobile operators, Facebook, or other (non-Google) social networks preinstalled.
So, it is maybe not perfect (you need the Open OS if you don’t want any data collection by Google) but not nearly as bad as some of the Android systems described in the paper. I do not know what the Qualcomm components on the phone are doing, but you need them for proper functioning of the phone as it contains a Qualcomm chipset.
Yes, you are mainly fine with the Android install you have when you first boot the phone. However, as stated, if you care about privacy, you should reinstall your phone with the Open version to remove every Google bits. This is needed if you don’t want tracking.