I'd have been fine with zero times watching it. Although it did prompt me to read several good articles about the actual events; which were very impressive. The bravery and sacrifice of those involved never really showed in the movie, it was just one slow moving 'event' after another. I can take war movies that cover battles that were just depressing and show what people went through because they had to and I enjoy ones that highlight triumph like hacksaw ridge but this skipped 99% of the triumph that existed for the reason of feel of the movie.
I just couldn't take the overly artsy, non-linear (nice way of saying it jumps all over) design; the silence for sake of silences when there was no way the soldiers wouldn't have said anything for so long. And now anytime I see the word Dunkirk I hear that awful high pitched background sound that played through most of it.
For Darkest Hour only touching on Dunkirk I thought it did a better job of conveying how important it was and how many small boats were involved. The single shot of all the boats heading across the channel in Darkest Hour was completely missing in Dunkirk. If someone knew nothing of the events at Dunkirk before watching Dunkirk it would shed very little light on how amazing it was.
Often a well told documentary can run circles around a Hollywood production. The Discovery Channel (or History Channel) did a special on the Black Hawk Down incident that was light years better than the movie.