I don't know how fast or slow my reading is, but I don't think I'm that fast because I want to read carefully and thoughtfully, so I take my time (some people can probably read quickly but still properly but I don't think I can do that, at least that fast). At the very least, I definitely cannot finish reading a whole game in a day or so like these people haha. Even though some stories can be boring, I still try to read properly and process what I am reading (as well as listen to the voice acting to get more context with how the lines are delivered) because I feel like that seems more respectful to the writer for me (no judgement to those who skip, etc, but this is just what I personally feel for myself and try to do). So if there are any plot points etc that I don't get, I stay there and reread it until I comprehend it, which means it's likely that I take longer.
Also, I try to binge or at least complete one entire game without too many gaps in between, because I want to concentrate and hopefully get absorbed in it to enjoy it more, and if I take a break for too long, I may forget or lose interest in the story (so this might result in finishing it faster, ideally). Of course, there are inevitably many times where I don't have the time to binge a whole story, which can result in losing motivation with finishing it if the break I take is too long, and as such, some games take very long to complete.