To anyone else who read this synopsis by Oplet (appreciate the summary, btw) and wanted some more context, I found this document particularly helpful in understanding contemporary Russian Foreign Policy:
https://www.understandingwar.org/report/how-we-got-here-russia-kremlins-worldview
(copy of the report attached to this post)
The report includes extensive citations and is definitely worth reading in it's entirety.
From the conclusion (pg 24, paragraph 6):
"The Kremlin believes that it must maintain control over its neighbors and preserve or expand its historic spheres of influence. Its rhetoric against NATO is less about its fear of a direct military threat and more about its fear of a loss of its power and influence. Putin often frames violations of others’ sovereignty as a defense of his own."
ISW Report_The Kremlin's Worldview_March 2019.pdf