I have a "trick".
My native language is not english. 99.9% of what i read is in english. Comprehension for me is also slow when just reading(at least once).
Memory, as i found out, works if you connect new knowledge to existing knowledge. Usually, when i read and understand something to the point of the "aha" moment is not sufficient. Just understanding something in that moment is not enough for storing in long term memory.
Here is the trick part: when i read and want to comprehend and memorise, i do the following:
1. Read a paragraph/piece in english
2. Get to the aha moment by re-reading until it makes a narrative in your head
3. Once i have the narrative, i translate it to my native language and write it down(pen and paper > keyboard)
1. first reading - getting the context of the material
2. getting to the aha moment - means it's connected to something, and the new knowledge somehow filled the gap
3. when i get to the narrative part, i can make a story and tell it to myself, in my own head "this is because of that etc"
4. #3 is not sufficient, so i take a step further and process it by translating it - further cementing the "connecting to old knowledge" process
5. #4 is also not sufficient, as the translation is not always clear when trying to explain it to someone else. here is where the longhand writing comes into play - writing is expressing your thoughts clearly. when this is done, i already went through a lot of phases of processing, that i can say i fully understand something without any rote memorisation: i can just use whatever old knowledge i have to recreate new knowledge and to assemble it based on the listener's (perceived) capabilities of understanding.
Not sure this helps you directly but indirectly it should be able to guide you into figuring out what works best in your context.
#edit: i still don't know how to format text in a comment
#edit 2: figured it out