Then you truly ignored the book of Acts and the end of the Gospels. There are various references to both gathering together on the first day of the week and remembering Christ’s (death, burial, and) resurrection.
1 Corinthians 16:1-2 Now concerning the collection for the saints, as I have given order to the churches of Galatia, even so do ye. 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.
1 Corinthians 11:26 For as often as ye eat this bread, and drink this cup, ye do shew the Lord's death t