Rest assured we are taking the documentation issue seriously. Here is the UX research I have started. https://indieweb.org/WordPress/Onboarding
The first step to good documentation is user research both through dogfooding but also through research,
Collecting user stories from users at different levels and doing cognitive labs with new users.
You would be in quite the sweet spot as someone who has struggled with documentation to interview for the study.
In terms off your FAQ and what happens to bridgy when I started working on this and trying each case: https://docs.google.com/spreadsheets/d/19l28iCNAcMiwL2Tpko0GhiLVAVyl9DPltNS8ZvumwoE/edit#gid=0 Once you get SemPress 100% setup you could do the same as a way of contributing as well.