Can a genuine Christian believe Jesus died on Wednesday, as long as he still agrees that he rose again three days later?
Yes.
In the grave before sundown on the 6th day, and rising at an unknown time before sunrise on the first day, is not 3 days and 3 nights in the grave.
There were multiple calendars being used at that time. The Pharisees had their calendar. The Sadducees had their calendar; and the sons of Zadok were using the Enoch calendar.
Here is a reference to the sons of Zadok.
(CLV) Ezk 44:15
Yet the Levitical priests, sons of Zadok, who kept the charge of My sanctuary when the sons of Israel strayed from Me, they shall come near to Me to minister to Me, and they will stand before Me to offer to Me the fat and the blood, averring is my Lord Yahweh.
(CLV) Ezk 44:23
They shall direct My people to distinguish between the holy and the profane, and they shall inform them the difference between the unclean and the clean.
(CLV) Ezk 44:24
In a controversy it is they who shall officiate in judgment; in accord with My ordinances, thus they will judge it; My laws and My statutes shall they observe at all My appointed times, and My sabbaths shall they hallow.
The sons of Zadok (The true priesthood) , were in Bethabara, beyond the Jordan, in wilderness, where there had been constructed very large mikveh pools fit for baptizing the masses. John the Baptist was a rightful priest in that same area, currently renamed as Qumran by Islam.
Yahshua would not violate the authority of the sons of Zadok (thereby YHWH), by honoring the Pesach by the Pharisee calendar.
Notice which day the Pesach meal is eaten on the Enoch calendar.
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The Pesach is slaughtered on the 3rd day; and it is eaten that evening, which begins the 4th day.
The last supper begins on Tuesday night by the Gregorian calendar; but sundown on Tuesday night, by the Gregorian calendar begins the 4th day by the Enoch calendar.
Yahshua hosted the Pesach meal at the beginning of the 4th day, also known as the 1st day of Hag Matzot, by the calendar of authority.
He was murdered during the day on the 4th day. He was buried during the day on the forth day.
Day one
The sun goes down on the 4th day, beginning the 5th day.
Night one.
The sun rises on the 5th day.
Day 2.
The sun sets on the 5th day
Night 2
The sun rises on the 6th day.
Day three.
The sun sets on the sixth day, beginning the 7th day shabbat.
Night 3
(CLV) Jn 20:1
Now, on one of the sabbaths, Miriam Magdalene is coming to the tomb in the morning, there being still darkness, and is observing the stone taken away from the door of the tomb.
(CLV) Mt 12:8
for the Son of Mankind is Lord of the sabbath."
The Master of the Shabbat was risen on the Shabbat.
I have more evidence that John the Baptist and Yahshua followed the Enoch calendar; but this is a good start.