My friend, I want you to understand the teachings of the Church so that you can one day enter the Church and be fully united with the Body of Christ. From what you have said, it seems that you misunderstand some important points regarding a Christian’s obligation regarding offering worship to God.
God’s rest on the seventh day is not the institution of the Sabbath in a strict sense because the Sabbath is a Jewish observance, and as you have rightly noted, Judaism did not begin at Creation.
Take even the 10 Commandments, since you’ve mentioned them. Christians are obliged to obey the moral precepts described in the Commandments, as well as all Mosaic and Levitical laws, but we are not obliged to follow the practical directives of the laws (such as abstaining from pork, stoning homosexuals, and observing the Sabbath). Christ Himself modified the Commandments for future Believers when He said
“You have heard it said…Thou shalt not covet thy neighbors wife (commit adultery). But I say anyone who looks at a women with lust has already committed adultery against her.” (Matthew 5:28) in this case Christ has changed the law of the 10 Commandments, and in fact made them more strict.
The Holy Sacrifice of the Mass and it’s observance on Sundays is not a tradition of man. The Mass itself was instituted by Christ Himself on Holy Thursday. And the Acts of the Apostles show in multiple scenes the Apostles and earliest Christians offering the Mass on Sunday.
Please, nearlycatholic, look into this subject very carefully. The resources on Catholic.com are a great start. The Mass is not the Sabbath. They’re totally different. One cannot move the sabbath from Saturday to Sunday because there’s nothing to move. They’re different things. Christ instituted the Mass and the Apostles celebrated it on Sundays and thus it is entirely a Divine and apostolic tradition.
There is no sabbath. Christ has fulfilled the old law and put an end to sabbath. If you really wanted observe the sabbath to whatever degree is possible, it would merit nothing and would be offensive to God because He has given you the means to offer worship to Him via the Mass.
God bless you, and I look forward to having you fully united to Christ’s Church.