Whether something is transformatice is often mentioned in an analysis of whether fair use applies to the use of copyrighted content in US law, but it is not even one of the four statutory factors, and is surely not the full analysis. Note that fair use is a strictly US legal concept, and does not apply in the copyright law of non-US countries. A fairly detailed fair use analysis was provided in an answer to Does Fair Use of copyright apply to educational youtube channels? and it is worth reading.
If the purpose is academic commentary and criticism, or is educational more generally, that tends to favor fair use. If the video could plausibly serve as a replacement of the original, so that people would be less likely to buy the original, that would tend to tilt against fair use. The less of the original used, the stronger the fair use case. But none of those have clear bright lines on where fair use starts or stops. Fair use is always highly dependent on the individual facts of the specific case.
Note that a copyright owner can sue in any country where an infringement occurs, which with things posted to the net generally means almost any country at all. The law of the country where the suit is brought would apply. Many countries have exceptions to copyright for comment and criticism. Also, in a suit in a country where the accused infringer has no assets and does little or no business, it is hard to obtain any damages, even if it is "won".
