Honestly, what I would suggest doing is playing another day and then TTing back to May Day AGAIN and doing the event yet again. You may be able to get the photo that way.
I haven't tried, but I heard that Nintendo removes the 2020 versions of holidays whenever they add in the 2021 version. The 2022 version of the holiday does not exist in the game yet, so it should act like a normal day without the event. I have the feeling that eventually, when Nintendo decides to completely stop doing event update support, they will add a patch that makes holidays always be the same every single year like all of the previous AC games.