Help. My Acrobat Reader won't open the propeties for comments and keeps crashing

Hi. I've had this problem before and the updates haven't really helped much. My Acrobat Reader DC Version 2018.011.20040. Keeps crashing on me whenever I open large PDFs such as textbooks, particularly the ones over 30MB which is unfortunately the greater majority of textbooks and school handbooks, especially for the sciences. Whether it crashes or not the properties for the comments won't open which means I can't add stamps or change the colors. Also whenever I write something I can't change the letter style, size or color even though the tab for that opens. It is also not letting me see the different sizes for the pages or really anything that requires opening a menu such as those found in the File, Edit, View, Window, and Help tabs. Is it possible that Acrobat is just not built to handle such large PDF files and if so is there an update for it that will allow it or a program that does? Please help, this is making my homework very hard to complete.