A demanding essay does not always reward a single uninterrupted reading. Separating orientation, close reading and review can make its argument easier to follow. Each pass serves a different purpose, so you do not need to understand every sentence immediately.
On the first pass, identify the topic, central question and broad structure. Read the opening and conclusion, then notice section headings or recurring terms. Write a tentative sentence about what the author appears to argue.
On the second pass, follow the reasoning carefully. Mark where evidence supports a claim and where the author addresses an alternative view. Keep unfamiliar terms in a short list instead of allowing every lookup to interrupt the thread.
For the final pass, close the text and explain its argument in your own words. Compare that explanation with the essay and correct omissions. Note one unresolved question. Understanding a text includes recognising where your reading is still uncertain.