Again I ask where in these verses does it say anything about Sunday to be kept holy? It just seems like it is a coincidence these things happened on a Sunday. The collections in I Corinthians 16:2 was made on a Sunday because that is the customary day when Jews made payments and settled accounts. This why Paul suggested they set aside money for the famine-stricken folk in Judea. It was not because Sunday was holy, rather it was because it made sense to set aside money on that day before they paid any bills. Only the fourth commandment says anything about any day being holy.
"One person esteems one day above another; another esteems every day alike. Let each be fully convinced in his own mind. He who observes the day, observes it to the Lord; and he who does not observe the day, to the Lord he does not observe it. He who eats, eats to the Lord, for he gives God thanks; and he who does not eat, to the Lord he does not eat, and gives God thanks" (Romans 14:5-6).
The critical fact is that your argument to ignore the gathering of funds is based on speculation, not on any evidence from the Scriptures or even from external sources. Second, it assumes that the church to which it was written was composed of people following Jewish traditions. But in this particular case, we are talking about the church in Corinth -- a Greek city. Yes, there were former Jews in its membership, but it was also composed of Gentiles as well. Your speculation doesn't hold any weight in such an environment, even if it could be proven. Third, you missed that Paul gave the same orders to the churches in Galatia -- which were mostly Gentile churches.
Yes, the Israelites were told to keep the Sabbath day holy. It was a command unique to them. As Moses asked, "And what great nation is there that has such statutes and righteous judgments as are in all this law which I set before you this day?" (Deuteronomy 4:8). Or as the Psalmist noted, "He declares His word to Jacob, His statutes and His judgments to Israel. He has not dealt thus with any nation; And as for His judgments, they have not known them. Praise the LORD!" (Psalm 147:19-20). The Old Testament was unique to Israel. "The LORD did not make this covenant with our fathers, but with us, those who are here today, all of us who are alive" (Deuteronomy 5:3). As God said through Amos, "You only have I known of all the families of the earth" (Amos 3:2).
This was one of many reasons the covenant was replaced. A covenant designed for one nation would not serve the whole world. "Therefore remember that you, once Gentiles in the flesh--who are called Uncircumcision by what is called the Circumcision made in the flesh by hands-- that at that time you were without Christ, being aliens from the commonwealth of Israel and strangers from the covenants of promise, having no hope and without God in the world. But now in Christ Jesus you who once were far off have been brought near by the blood of Christ. For He Himself is our peace, who has made both one, and has broken down the middle wall of separation, having abolished in His flesh the enmity, that is, the law of commandments contained in ordinances, so as to create in Himself one new man from the two, thus making peace" (Ephesians 2:11-15).
As Paul told the Gentiles who had become Christians in Colosse, "In Him you were also circumcised with the circumcision made without hands, by putting off the body of the sins of the flesh, by the circumcision of Christ, buried with Him in baptism, in which you also were raised with Him through faith in the working of God, who raised Him from the dead. And you, being dead in your trespasses and the uncircumcision of your flesh, He has made alive together with Him, having forgiven you all trespasses, having wiped out the handwriting of requirements that was against us, which was contrary to us. And He has taken it out of the way, having nailed it to the cross. Having disarmed principalities and powers, He made a public spectacle of them, triumphing over them in it. So let no one judge you in food or in drink, or regarding a festival or a new moon or sabbaths, which are a shadow of things to come, but the substance is of Christ" (Colossians 2:11-17).
The point isn't whether the Israelites were told to keep the Sabbath holy. The point is that Christians were not told to keep the Sabbath holy. Instead, they were told the opposite, that no one was to judge (condemn) them regarding keeping Jewish holidays and holy days.
Wiggle all you want, but you have failed to avoid the fact that Christians worshiped on the first day of the week.