Part of "higher criticism" is simply guessing and rationalizing. It is skepticism without restraint. A truly open and scholarly mind does not speculate and then publish such an unprofessional unsubstantiated speculation off of guesswork.
For me: True, there is currently little evidence 'from Egypt' regarding an internment of Israelites in Egypt. Why would they? They weren't Egyptians nor highly regarded. A lack of evidence on that point, doesn't mean much. Writing in stone normally took a mandate. People didn't record willy nilly and only the scholarly, employed by kings, would have recorded much of anything. Papyrus didn't last, etc. Until the Dead Sea Scrolls were found, higher criticism 'scholars'
decided Daniel couldn't have been written by Daniel because it was too accurate. It was nothing but skepticism and incredulity expression guised as 'scholastics' but was anything but and people were foolish to readily accept such nonsense hook, line, and sinker.
Skepticism is rarely a friend to truth. Time and patience serve incredibly better. Frankly, it is not reasonable to doubt a whole culture and national heritage, religious or not. Imho, it is most often dishonest attack always politically and/or religiously motivated and entirely forgettable and unfounded nonsense from those with no vested interest. They are always disinterested skeptics with a less than stellar or honest agenda. Literally, there is no 'good' reason for it.