If you are really interested, there are thousands of references at your fingertips. The book of Hebrews clearly says that Jesus is not an angel. Hebrews 1:5 , 13-14
I first read about SDA’s in a book entitled “Kingdom of the Cults”.
So you came into this thing with a bias, from a book that looked for every possible thing to smear them with.
To wrongly believe the preincarnate Christ appeared as such and such a figure (and the question about the preincarnate Christ appearing as “the angel of the Lord” of the Old Testament is a frequent one in evangelical circles) is not the same as calling Christ a creature. One can be “wrong” without “blaspheming.” They are saying Michael was a being higher than he probably was, not that Christ was lower.
Agenda driven smear people really tick me off.
The book you cite and it’s author were discredited a long time ago. I seriously doubt your charge but would be willing to consider it if you had a good and verifiable source(s). I have been around 7th Day Adventists for many years and never heard such a thing as you charge,