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 till he come.
Jesus can’t return to gather the saints and establish His kingdom if He is not alive to do so.
Just to clarify: what are you asking or debating here exactly? Denying or questioning they gathered on the first day of the week, or that they specifically remembered (or celebrated in some way) the fact that the Lord Jesus Christ arose? It’s hard to give specific passages when I am not sure what you are looking for.
The New Testament is full of references to the resurrection of Christ, and the book of Acts (and even 1 Corinthians) contain various references to believers meeting together on the Lord’s Day/Sunday.