@veryalien I received my 16gb cards yesterday and they worked :)
It's rather odd that I have to restart the test app after each insertion/removal to get it to work but they do work.
Note too that you have to use the CS value (of 4) for SD.begin() to work, too bad this isn't documented in the examples (see SD_Test.ino in arduino IDE)
Things are better now, but I can say that 16gb is a ridiculously low value for storage on a 2020 device :(
Now I have to figure out how to implement the home automation bit -> it sure would be nice to connect to my alexa skills and go from there.