There is no scripture that implies JESUS told His Disciples to 0bserve sunday...none whatever, nor His Followers. Rather we are told to ''follow his steps'1Pt 2v21. JesusALways kept His Fathers Commands and did not come to abolish. He was obedient unto death and never changed. All that is seen from scripture.
When we read about BELIEVERS gathering and starting to do their own thing it was much later...after Jesus and the original Disciples had been persecuted and killed and UNGODLY men had infiltrated the church/body of Converts, that sunday became the worship day....instigated by the RCC under threat of death if people continued in the ''jewish ways'.....still called so today by all who hate the Sabbath.
When it comes to Rom 14 there is massive MISunderstanding which also results in Sabbath-breaking. Paul never told people to choose their own day...rather he said ''that it was something SOME were doing. He never instructed any to follow them. Paul did say 'to follow HIM as he FOLLOWED CHRIST, which was obviously Sabbath-keeping 1Cor 11v1.
It is true in the NT we have no command specifically to keep Sabbath holy because we are now in the era of 'Grace .that needs not to be COMMANDED but obeyed through LOVE ! We should have matured to a BETTER way and relationship with God and Christ ...but it will never be without law and order. OBEDience to GOD will always remain or we will NOT be in His Kingdom Mat 7v21.
This is quite a depressing read, because I would like to say that you are mistaken or that you have misunderstood the scriptures, but the truth is I can't argue against what you've said.
I spent a bit of time, looking to the pro's and con's of Sunday worship and found a minefield of different views. I had to retreat without taking a stand and I don't like doing that, I like to be on the winning side all the time. But on this matter, I don't see a clear winner.
I'm actually disturbed by my findings, I read that the Roman Church changed the "Sabbath" as the day to set aside for the Lord to Sunday, I am vehemently opposed to Romanism. I don't want to be seen as going along with their Pagan feast days.
I haven't reached a firm decision in this matter, so I will take my time and learn as much as I can before I make a final decision about it. I spent around 6 months in a SDA Church, they convinced me that they were a truly Biblical Church.
It wasn't until I found out about their founder Ellen White and her extra Biblical revelation, that caused loud alarm bells to ring in my head and I got out of there like a bat out of hell. I have been shy about this issue since then, but I have to revisit the issue and put it to bed once and for all.