How do I match a literal question mark character in a REGEXMATCH formula in a Google Sheets Custom Formula filter? I am trying the below to omit rows that have "na" or "?" in column E, but it filters out ALL rows... I have already tried escaping the question mark with a tilde, as well as 1,2,3,4, and 5 backslashes, to no avail. Greatly appreciate any help!
=not(regexmatch(E:E, "na|?"))