This passage may not be original. Paul was a proud Jew, yet we see in 1 Thessalonians 2:14-16 that he castigates the Jews, speaking of them in the third pary, in spite of being a Jew himself:
For you, brothers, have become imitators of the churches of God that
are in Judea in Christ Jesus. For you suffer the same things from your
compatriots as they did from the Jews, who killed both the Lord Jesus
and the prophets and persecuted us; they do not please God, and are
opposed to everyone, trying to prevent us from speaking to the
Gentiles that they may be saved, thus constantly filling up the
measure of their sins. But the wrath of God has finally begun to come
"The wrath of God has finally begun to come upon them" may be a reference to the destruction of the Jerusalem temple, in which case this would be an interpolation that could be dated to later than 70 CE. There was no other recent calamity that Paul could have been speaking of in terms of the wrath of God coming on the Jews.
Verse 2:16 accuses the Jews of "trying to prevent us [Paul] from speaking to the Gentiles that they may be saved." Then in 2:18: "Satan hindered us."
I believe that verse 2:18 is part of the anti-Jewish polemic I cited above, meaning that the interpolator was referring to the Jews by the pejorative "Satan."