its hard and its not just you, and this is not "kids these days with their iphone no attention span". theyre pretty heavygoing books discussing big concepts anyway, so theyre gonna be hard however theyre written. but then theyre written using old timey terminology that might have made sense then but isnt in common use now. and some of them were references to concepts that meant one thing then and something different now ("value" being an obvious one). and then tonnes of references to thinkers who were probably mainstream in the day but nobody remembers now, and events that were recent and everybody knew about, and even just assumptions about the general makeup of society and production and commodities etc etc that are very different from now, plus everything is measured in weird shillings and shit which is impossible to have a feel for how much any of that is etc etc. and they probably could have used some editors as well - marx in particular loves these ridiculous run-on sentences where by the time you get to the end youve completely forgotten what he was talking about at the start.

id maybe suggest trying to find a good youtube video by someone reputable to help walk you through some of them, and im particularly thinking of the excellent david harvey lecture series on capital, which makes it a million times more comprehensible even though its more time-consuming.