The Sabbath is on Saturday, fren.

Mark 2:27

And he said unto them, The sabbath was made for man, and not man for the sabbath

Like Christmas and Easter, Sunday has pagan origins and is not Biblical.

Easter falls on the Spring Equinox. The Pope announces changes to the date of observance on years that date happens to be too close to Nisan 15 (Passover on Jewish calendar). The colored eggs used to be colored red with the blood of sacrificed chikdren. Easter bunny is most definitely not Biblical.

The pagan celebration of the Roman god, Saturn, first began as a single day, but later extended to a whole week during the late Republic. The festival began on December 17 of the Julian calendar, which the Romans used in those days, and initially ended on December 25, the time at which the winter solstice fell. During the celebration period, all activities came to a halt. Businesses, courts, schools, and other social patterns were suspended while people spent time doing more fun activities. Slaves were allowed to take part in the celebration and even reversed roles with their masters. Feasting, playing, gambling, singing, exchanging gifts and home decorations were some of the activities people enjoyed doing during this time. Thus, the Saturnalia celebrations are the source of many traditions associated with Christmas.

https://nationaltoday.com/saturnalia/