@Scott by when can we expect a newer version of this course?
Not that information isn’t valid but doesn’t cover the new stuff, like transit gateways, privatelinks, control tower, DMS, SCT etc.
I don’t think I am the Scott you wanted to answer, but have you checked out some of the re:Invent videos linked under each section’s Exam Tips? That’s how I learned about Control Tower and got more in-depth coverage about SCT and DMS. I believe Private Link is mentioned within the course, or at least the videos. I have also found that incorporating all of the AWS FAQS, and sometimes the documentation for key concepts like VPCs, to be very valuable.