Have you tried using the "from text/csv" importer under the data tab? Where it will import your data into a table. Because that one will import ISO 8601 timestamps just fine.
This, it's dumb but Excel handles csv way better if you 'import' it vs just opening it. I use excel to quickly preview csv files, but never to edit them unless I'm OK only ever using it in Excel afterwards.
Even in that case I'd be hesitant to open a CSV file in excel. The problem is that it will automatically apply whatever transformation it thinks is appropriate the moment you open the file. Have a digit string that isn't semantically a number? Too bad, it's a number now, and we're gonna go ahead and round it. You didn't really need _all_ of the digits of that insurance policy number, did you?
They did finally add options to turn off the common offenders, but I have a deeply ingrained distrust at this point.