Also you see the "extra" where one does not exist.
“the Jewish reckoning of “a day and a night” is an idiom. it refers to any part of a 24 hour period”
I agree and would also add that the insistence upon three full days and nights also causes trouble with other verses that say he rose on “the third day.” I suppose you could call Thursday the first day (although Wednesday would be the day He died in this theory), but even then Saturday would be the third day. But you can’t really get around Luke 24:21, on the road to Emmaus, after the empty tomb has been found on the first day of the week, when the disciples say “today is the third day since these things happened.” Sunday is the third day, not Saturday.
This is the sequence of the burial and resurrection in Luke:
Luke 23:55–24:2 And the women who had come with Him from Galilee followed after, and they observed the tomb and how His body was laid. Then they returned and prepared spices and fragrant oils. And they rested on the Sabbath according to the commandment. Now on the first day of the week, very early in the morning, they, and certain other women with them, came to the tomb bringing the spices which they had prepared. But they found the stone rolled away from the tomb. (NKJV)
There is a chapter break right before “Now on the first day of the week” which makes it easier to get away with trying to add another regular day and another sabbath day in between, but the chapter is an artificial break added after the fact. They were on the way to the tomb at the absolute first opportunity to do their work.