I stand corrected, its been quite a few years since I needed to use the ADB backup so I guess back then it was more complete.
Found a good detailed explanation here.
Shame that it seems to be getting phased out for cloud backup solutions. Makes sense that google would want to control more of your data and make you pay for it.
GrapheneOS also has this cool feature called Scramble PIN Layout to try and protect against guessing the pin from fingerprints on the screen.