The afternoon sacrifice of the passover lamb takes place on the fourteenth day of the first month of Aviv. God’s first set of holy days begins at sunset, the beginning of the fifteenth. This first day of unleavened bread was an annual Sabbath day that could fall on any day of the week, as it was determined by the date rather than the day, similar to your birthday. So if the fifteenth was a Thursday then that Thursday would have been a special annual Sabbath day, making Wednesday the fourteenth the evening the passover lamb’s blood was painted on the doorposts.
The days of unleavened bread lasted for seven days and had an annual Sabbath on the first and last day. Those seven days would also include a weekly Sabbath unless the first or last day landed on the weekly Sabbath. Hypothetically using Thursday as the first annual Sabbath day, Jesus would have been crucified and died on Wednesday just before sunset as the passover lambs were being slain.
John 19:31 Easy-to-Read Version
31 This day was Preparation day. The next day was a special Sabbath day. The Jewish leaders did not want the bodies to stay on the cross on the Sabbath day. So they asked Pilate to order that the legs of the men be broken. And they asked that the bodies be taken down from the crosses.
Friday would be a regular work day for the people, they just had to abstain from eating or using leavened products. As usual, that Friday would be the preparation day for the weekly Sabbath day arriving with the sunset. Sunday, Monday would also be normal days with the exception of the special unleavened diet. Tuesday would have been slightly different as it would be the preparation day for the last special annual Sabbath of that year’s seven days of unleavened bread season. It lasted for seven days bookended by special annual Sabbath days. Wednesday, starting at sunset Tuesday, would be the last annual Sabbathday and it would be observed until Wednesday evening’s sunset.
Exodus 12:14-16 English Standard Version
14 “This day shall be for you a memorial day, and you shall keep it as a feast to the Lord; throughout your generations, as a statute forever, you shall keep it as a feast. 15 Seven days you shall eat unleavened bread. On the first day you shall remove leaven out of your houses, for if anyone eats what is leavened, from the first day until the seventh day, that person shall be cut off from Israel. 16 On the first day you shall hold a holy assembly, and on the seventh day a holy assembly. No work shall be done on those days. But what everyone needs to eat, that alone may be prepared by you.
So far these special days were to commemorate what God did to free the Israelites from Egypt. Understanding how God set out his days of worship helps with determining the days Jesus died and was resurrected, before sunrise three days later. Do you think Constantine was concerned with biblical dates and times when he instituted Good Friday and Easter Monday?