The Acts quote says they came together on the first day of the week to break bread. That allows the interpretation (but does not establish) that they broke bread in the manner of the Eucharist, i.e. the Lord's Supper, ie. the Lord's Body and Blood. It also allows the interpretation that they just came together for a meal.
It says they did it (once) on the first day, but doesn't say they did it regularly, or always, or exclusively on the first day. As a stand-alone verse, it's too vague to tell us exactly what they were doing, let alone what we should do. Nor does it --- in itself --- dis-establish the Sabbath (seventh) day as the Lord's Day.
The second quote (Romans), as a stand-alone, basically says, "This day, that day, whatever...." It precisely does NOT establish the first day of the week as a day dedicated to the Lord.
So I don't see how one can draw the desired conclusion from these two verses alone. Maybe you want to add something else?
Or even the fact the the LAWs were a CONTRACT between the 'chosen people' and GOD - NO one else.
Here are two MORE verses...
Jesus answered, “The work of God is this: to believe in the one he has sent.”
1 John 3:21-24
Dear friends, if our hearts do not condemn us, we have confidence before God and receive from him anything we ask, because we keep his commands and do what pleases him. And this is his command: to believe in the name of his Son, Jesus Christ, and to love one another as he commanded us. The one who keeps God’s commands lives in him, and he in them. And this is how we know that he lives in us: We know it by the Spirit he gave us.