I don't see it that way. There's loads of biographical material in the Gospels, but the essential message is there in Paul.So, in that regard, no matter what Paul may have written or not written, or even, say, Peter, in his epistles, it is just their commentaries to the Word.
And the Gospels are really the Evangelists' commentaries on the evangelium they received from the apostles, from the ekklesia, and from the immanent presence of the Holy Spirit.
Of the four, only John claims to have seen Christ. Paul claims to have seen Christ, so on that basis, it arguably shifts his understanding onto a more immediate footing than the Synoptic scribes.
If, for example, we only had Mark, then what have we got? An empty tomb, and an enigmatic ending.
Is that because the written Gospel agrees with Paul?And for instance, what Paul says that in Christ is the fullness of the Divinity bodily is quite in agreement with the Gospel,