I suggest using the spreadsheet to create a URL scheme for each task and then opening those URLs via Shortcuts. The formula to create the URL scheme in numbers would be something like this:
(Full URL scheme documentation is available here: https://support.culturedcode.com/customer/en/portal/articles/2803573)
Then you copy that new column, and run something like this shortcut: Open Clipboard URLs. In my experience the URL action encodes any characters it doesn’t like, so that should work.
Another approach is to put the data on your clipboard as a CSV and then run something like this shortcut: CSV Clipboard to Things, you need to specify the column numbers for the titles and deadlines on import.