Paul taught that Antichrist comes before the Lord — not the date; the restrainer is in the letter
Paul did not teach a date — only that Antichrist comes before the Lord's return, and what delays him.
He says you know what restrains — not you know the hour of the man of sin.
The same restrainer is repeated in the letter itself until he is taken out of the way.
Oral clarity may have helped hearers; tradition still adds nothing beyond the written hint.
Latin
XX. Sed quod ad rem ipsam attinet, Apostolus non innuit se docuisse Thessalonicenses quando venturus esset Antichristus, sed simpliciter illum venturum esse ante secundum Domini adventum, ac praeterea quid tardaret Antichristi adventum. Et enim non dicit, scitis quo tempore venturus est homo peccati, sed simpliciter, nunc quid detineat scitis. Quid autem esset illud, non tantum viva voce docuerat ante Apostolus, sed postea repetit & confirmat in hac ipsa epistola, Tantum enim, inquit, qui nunc retinet, retinebit, usque dum e medio tollatur: Et tunc revelabitur iniquus ille. Obscure ista quidem, quae forsan clarius & uberius viva voce explicuerat Paulus, sed quicquid sit traditio nihil hic ad Scripturam adjicit, neque ex ea habemus quicquam amplius de iis quae paullo innuit Apostolus.