For those who have believed the gospel and been baptised into Christ there is no commandment given which requires them to observe the feast of Passover and unleavened bread.
Observation of the Passover and unleavened bread was required under the Old Covenant made with Israel at Sinai. This covenant was ratified by the blood of animals.
Christ fulfilled the Old Covenant and removed it.
He established a New Covenant ratified by his own blood.
Under the New Covenant we are to share bread and wine in remembrance of Christ’s sacrifice.
1 Corinthians 11:23 For I have received of the Lord that which also I delivered unto you, That the Lord Jesus the same night in which he was betrayed took bread: 24 And when he had given thanks, he brake it, and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me. 25 After the same manner also he took the cup, when he had supped, saying, This cup is the new testament in my blood: this do ye, as oft as ye drink it, in remembrance of me. 26 For as often as ye eat this bread, and drink this cup, ye do shew the Lord’s death till he come. 27 Wherefore whosoever shall eat this bread, and drink this cup of the Lord, unworthily, shall be guilty of the body and blood of the Lord. 28 But let a man examine himself, and so let him eat of that bread, and drink of that cup. 29 For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord’s body.
This meal is not restricted to being observed once a year.
It was observed by the first century Christians on the first day of the week and this has become the tradition.
Acts 20:7 And upon the first day of the week, when the disciples came together to break bread, Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight.
1 Corinthians 16:2 Upon the first day of the week let every one of you lay by him in store, as God hath prospered him, that there be no gatherings when I come.
The commandment is to observe it ‘often’ – no day is specified and it can be done on any day of the week.
All other observations, Lent, Easter, Christmas, etc. are ‘commandments of men’ and have no place in the New Covenant.
I hope you find this helpful.