One Gospel: Galatians 1:6-9, 2 Corinthians 11:4, Ephesians 4:5.
All of these verses utilize vocabulary of a singular Gospel, such as "the Gospel." The only mention of multiple gospels, in plural form, is when describing false gospels.
Your "one gospel" is a made up term and idea as is your "false gospel". The gospels that were preached in the Bible are real gospels to whom they were preached and will be preached!
the gospel of the kingdom,
the gospel of God,
the gospel of the circumcision,
the gospel of the uncircumcision
the gospel of Christ,
the gospel of the grace of God
and
the everlasting gospel (preached by an angel in Revelation)
ALL VERY REAL gospels, but not all good news (gospel equals good news) "unto you", "unto you", "unto you". The key to the verses in Galatians is "unto you". The gospel of the kingdom is not good news "unto you". The gospel of the circumcision is not good news "unto you". The gospel of God is the WHO of Jesus Christ and is not good news "unto you" (salvation wise). The gospel of Christ is the good news that Christ died for "our" sins and that He was buried and rose again the third day (but was only made known to be to those to whom Paul was first sent /the "our" in the passage). The gospel of the grace of God is the word of truth, the gospel of our salvation (the gospel that Paul preached "unto you"); that when Christ died for sins, He died for ours/we were included/all men sending that all can be saved by trusting the Lord believing it (1 Corinthians 15:1-4 KJV, 2 Corinthians 5:19 KJV, 1 Timothy 2:4-6 KJV, Ephesians 1:13-14 KJV, Ephesians 3:1-9 KJV).
Galatians 1:8 But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
Galatians 1:9 As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed.
Paul: Paul is the apostle to the Gentiles. I never said he was not. But that is the key: context. Apostle "to" the Gentiles. "Of" meaning "sent unto" or "coming from." This is easily found when consulting a dictionary.
It's the office of the apostle OF the Gentiles. A desk no one else held title.
Romans 11:13 For I speak to you Gentiles, inasmuch as I am the apostle of the Gentiles, I magnify mine office:
He is the apostle we are commanded to follow (1 Corinthians 4:15-16 KJV).
The 12 were commanded to go not into the way of the Gentiles (Matthew 10:5-6 KJV). I wonder why you go to a place where they claim to follow Peter?
I have nothing against Paul. What I have issue with is people who falsely claim that the first dispensation of Grace was into Paul, which goes against the Scriptures.
Contrariwise!
1 Corinthians 9:17 For if I do this thing willingly, I have a reward: but if against my will, a dispensation of the gospel is
committed unto me.
It doesn't say us. It says it was committed unto Paul!
And later:
Ephesians 3:1
For this cause I Paul, the prisoner of Jesus Christ for you Gentiles,
Ephesians 3:2 If ye have heard of
the dispensation of the grace of God which is
given me to you-ward:
Ephesians 3:3
How that by revelation he made known unto me the mystery; (as I wrote afore in few words,
Ephesians 3:4 Whereby, when ye read, ye may understand
my knowledge in the mystery of Christ)
Ephesians 3:5 Which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit;
Ephesians 3:6 That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel:
Ephesians 3:7
Whereof I was made a minister, according to the gift of the grace of God given unto me by the effectual working of his power.
Ephesians 3:8
Unto me, who am less than the least of all saints,
is this grace given, that
I should preach among the Gentiles the unsearchable riches of Christ;
People who only "believe" Paul, or rather, their version of what Paul is "saying." Many times, such individuals are doing some very impressive mental gymnastics to arrive at their doctrine, rather than just believing what is plainly written. Such an example is your version of Galatians, where you seem to just ignore the phrase "the gospel of Christ," a phrased denotation of a singular (one) gospel.
I believe all of the Bible recognizing that while all scripture is FOR us, it's not all to us or about us. I recognize that the Lord and the 12 were sent to Israel and that Paul was sent to us. We follow him and hold fast the form of sound words we have heard of him. Your "you're not believing what is written" doesn't work on a Bible believer. The gospel of Christ is the gospel that Paul preached "unto" the Galatians. That doesn't mean that it's the only gospel in the Bible (as demonstrated above). If one (Paul includes himself) was to preach any other gospel than the gospel of Christ "unto the Galatians Paul said let them be accursed.
As stated before, the Gospel of Salvation is the exact same one (singular) taught by Christ and His Apostles. Unchanging since Christ's life.
Wrong! Peter and the 11 did not even know that Christ would die (Matthew 16:21-22 KJV) let alone for anyone's sins! And as stated before, Paul's gospel was a mystery and he told us why (1 Corinthians 2:6-8 KJV). And the fact that it would reach us: a mystery not made known unto the sons of men/unsearchable/ hid in God (Ephesians 3:1-9 KJV)!
We must 2 Timothy 2:15 KJV!