I was recently learning Megillat Esther (as I prepare some shiurim on the topic), and was surprised to find the following comment by Rabbi Moshe Yitzchak Ashkenazi (Tedeschi), in his commentary to Esther 3:7:
ומחדש לחדש – חסרה כאן שיטה אחת שלימה ״ויפל הגורל בשלשה עשר לחדש״ והמעתיק שגה ברואה ועבר מן תיבת לחדש שבשיטה העליונה אל לחדש שבתחתונה.
And from month to month - an entire line was omitted here: "and the lot fell on the 13th day of the month", and the copyist misread it, jumping from the word "lechodesh" on the upper line to the "lechodesh" on the lower line.
Rabbi Ashkenazi was a student of Shada"l, who was of the opinion that it is permissible to make textual emendations only in the books of Nevi'im and Ketuvim, but not the Torah (see footnote 62 here). I was nevertheless surprised by this comment because a) I am not aware of heavy criticism levelled against Rabbi Ashkenazi, whereas such criticism of Shadal is fairly well-known, b) because Hoil Moshe is found in more traditional places, such as on Hebrewbooks (link), and c) because this strikes me as a more significant emendation, since it suggests that an entire line of the Megillah was missed.
So, my follow-up question(s):
Is it (halachically?/hashkafically?) permitted to suggest that the text of books in Nevi'im and Ketuvim is inaccurate? May one engage in textual criticism of these books, or is that considered inappropriate? Which (other) halachic authorities permit such a practice?
Note: This answer seeks Orthodox responses; I am aware of https://schechter.edu/is-it-permissible-to-study-biblical-criticism/