Already addressed above. Even the King James translators -- a very large company of devout and learned men -- identified the writer as Paul. The title of the epistle in the original KJV is "The Epistle of Paul the Apostle to the Hebrews".
Appeal to authority fallacy.
The article I linked to, on the other hand, made actual arguments based on the text of scripture and the message therein. Not the least of which, I alluded to by pointing out that Paul received "his gospel" by direct divine revelation.
Galatians 1:11 But I make known to you, brethren, that the gospel which was preached by me is not according to man. 12 For I neither received it from man, nor was I taught it, but it came through the revelation of Jesus Christ.
Galatians 1:15 But when it pleased God, who separated me from my mother’s womb and called me through His grace, 16 to reveal His Son in me, that I might preach Him among the Gentiles, I did not immediately confer with flesh and blood, 17 nor did I go up to Jerusalem to those who were apostles before me; but I went to Arabia, and returned again to Damascus.
18 Then after three years I went up to Jerusalem to see Peter, and remained with him fifteen days. 19 But I saw none of the other apostles except James, the Lord’s brother. 20 (Now concerning the things which I write to you, indeed, before God, I do not lie.)
21 Afterward I went into the regions of Syria and Cilicia. 22 And I was unknown by face to the churches of Judea which were in Christ. 23 But they were hearing only, “He who formerly persecuted us now preaches the faith which he once tried to destroy.” 24 And they glorified God in me.
2:1 Then after fourteen years I went up again to Jerusalem with Barnabas, and also took Titus with me. 2 And I went up by revelation (i.e. he was not summoned by the twelve), and communicated to them that gospel which I preach among the Gentiles, but privately to those who were of reputation, lest by any means I might run, or had run, in vain. 3 Yet not even Titus who was with me, being a Greek, was compelled to be circumcised. 4 And this occurred because of false brethren secretly brought in (who came in by stealth to spy out our liberty which we have in Christ Jesus, that they might bring us into bondage), 5 to whom we did not yield submission even for an hour, that the truth of the gospel might continue with you.
2:6 But from those who seemed to be something—whatever they were, it makes no difference to me; God shows personal favoritism to no man—for those who seemed to be something added nothing to me. 7 But on the contrary, when they saw that the gospel for the uncircumcised had been committed to me, as the gospel for the circumcised was to Peter 8 (for He who worked effectively in Peter for the apostleship to the circumcised also worked effectively in me toward the Gentiles), 9 and when James, Cephas, and John, who seemed to be pillars, perceived the grace that had been given to me, they gave me and Barnabas the right hand of fellowship, that we should go to the Gentiles and they to the circumcised.
vs.
From the Epistle to THE HEBREWS...
Hebrews 2: 3 how shall we escape if we neglect so great a salvation, which at the first began to be spoken by the Lord (i.e. during His earthly ministry), and was confirmed to us by those who heard Him (i.e. the twelve),
Paul's office, ministry and message are all categorically antithetical to the idea that he is the author of the Epistle to the Hebrews. He definitely did not write it.
That's only one of several biblical arguments. It's the only one that necessary but there are others that I could present but likely won't because based on your citing of the translators of the King James Bible as your authority, it would be wasted on you as the above likely will be as well.
Clete