Hi. Do you know how I can grab the textual date and convert it to YYYY-MM-DD
format in a new column?

The DATE function will try to convert any entry to a date format
(maybe string to date) Then just 1- choose a date format YYYY-MM-DD in
the cell
OR 2- convert it again to a new string in the new format with the
function TEXT( date ; "YYYY-MM-DD")