Jesus appointed Paul, so you are mistaken. Paul knew 0 of God being a trinity. Here is what Paul taught-1 Cor 8:6--There is one God to all the Father.See how Paul the self appointed Cult leader goes about his tasks of making up things . Same guy that dreamed up the Trinity Fake News which gullible cult Christian’s then thought made their story more mysterious and wonderful . He would have made a great CIA director .
Catholicism= the great apostasy( 2Thess 2:3) turned God into a trinity at the council of Constantinople in 381 ce, they added the holy spirit as part of a godhead at that council. Paul was long dead.