Vidqun : Bottom line is, you cannot use words or a language to date a document.
Now we have another method : radiocarbon and AI-based writing style analysis. There's no getting away from AI. In an article this month, Dating ancient manuscripts using radiocarbon and AI-based writing style analysis, PLoS One 20(6), it shows that carbon-dating and AI analysis predict some manuscripts are older than palaeographic estimates.
Of particular interest to the book of Daniel is the dating of the Dead Sea Scroll, 4Q114, which contains Daniel 8-11. Many scholars believe it was written during the Maccabean revolt (167-160 BCE) but carbon-dating and AI analysis give it a calibrated range between 230 and 160 BCE which rather stretches the date of writing unless 4Q114 is the "original" Daniel and not a copy. Now that would be a first.