In case you haven't read the SoD.
Canons of Dort - text(or Synod of Dort) full text
As for the comment that Reformed Theology's Gospel is different than the Gospel in the Bible, that's true.
One of the largest Denominations under the RT umbrella is Calvinism.
In brief, Reformed Theology declares that Jesus died only for those lost souls whom the Father gave Him to save before the world, much less sin itself, came to exist.
And those persons are totally depraved as natural born sinners until God's Holy Spirit enters them so as to make them to be that chosen one, "the elect", who are then able to comprehend the Gospel Good News, and then God makes them to have faith in what they're being taught, as that Gospel Good News.
Because, their God Given Total Depravity makes them in their natural state as one Totally Depraved, unable to understand anything of God.
None of this was taught by Christ. The well known verse in The Book of John chapter 3 verse 16 itself refutes in toto RT's declaration.
For God so loved
the world
That He gave His only Begotten Son
That
Whosoever believes in Him
Shall not Perish (in their sins)
But have immortal life.
The keywords in that single verse are bolded as that which renounces RT's doctrine in its entirety. RT actually blasphemes God by making Him out to be an immoral monster. An all knowing creator that creates a human race totally incapable of comprehending spiritual things, and in that God given state are damned to Hell. Unless or until any one in that population of humans is a chosen one, an elected one, of God so as to be made , not by their own choice because the Totally Depraved are incapable of exercising free will/choice of their own accord, but because God made them to be in His grace. And then once there , He made them to be able to hold faith in His word. Something they were made, by God and at their birth, prior to this God given transformation into grace and faith, incapable of doing.
Jesus died only for those people God would change like that.
RT also teaches Double Predestination, which what I just described is in a nutshell known as, Predestination. But Double Predestination is the belief that not only all that I posted above is a matter of God predetermining whom He would put into His grace and bring to faith but, He also predetermined whom would be born so as to perish in their sin and go to Hell. All before anything came to exist.
Think about what all that says about God.
I'll help; We're all pawns, and God is the back row in this chess game where some of us pawns will be saved from God. And some will go to Hell thanks to God.
That's why RT rewrites the actual Gospel to its own ends.