You can't lump the Ten Commandments in with the Mosaic Law as a "box set" when the Bible repeatedly makes clear distinction between the Moral Law and the Mosaic Law.
Or, do you not know that such a distinction exists? I mean, I've shown you just one proof of that by Paul's words about the one Moses wrote being nailed to the Cross, while the other that Jesus wrote is to "stand fast forever and ever".
There is no such distinction in the law of Moses. The ten commands are absolutely part of that covenant to the point of it being called the covenant, and all of it had to be kept as one body of law, down to the least jot and tittle.
It’s called mosaic law, not because Moses dreamed it up and invented it, but because God gave it to him.
It is one body of law, which is why Paul warns if a Christian keeps any part of it, they are required to keep it all, not just the part they like such as keeping Saturday, but all 613 parts of it.
The Decalogue kills but the two love commands that replace them bring life.
The ten commands as regards man’s treatment of his neighbor are negative commands, limiting the bad behavior towards them by threat of death if they don’t keep them. Dont kill him, don’t steal from him, etc, or die.
The two love commands are positive commands that results in not hurting your neighbor because you love him,
and goes far beyond the ten commands in how well you treat him - not just refraining from hurting him, but doing a great deal of things for him, out of love.
That’s why the two commands aren’t just redundantly restating the Decalogue- they are completely different and the two commands are far superior to the ten.
As an illustration, the neighbor on one side of your house confides that he’d like to steal all your goods, rape your wife, then kill you both, but he’s trying hard not too, because the ten commands say not to. Or the neighbor on the other side, who when you tell what the first neighbor said and ask him if he’s tempted to also do any of those things, says, no, why would I want to do that? I love you, i only think of helping you, not hurting you.
Which neighbor would you rather have?
And Paul also warns if you put yourself back under the law you fall from grace and make Christ of no effect unto you.