Signs and wonders were for large groups of people who needed to know (1) that Christ (the Messiah/King of the Jews) was God manifest in the flesh and (2) that the Gospel of the Lord Jesus Christ had a divine origin, therefore God was confirming it through signs, wonders, and miracles by the hands of the apostles and their companions.
People still need to know that.
At the same time, EVEN THOUGH CHRIST DID THOUSANDS OF MIRACLES the majority of Jews in the end rejected Him. Therefore He told His enemies that the only sign that they would be give was the sign of the prophet Jonah. Which meant that the resurrection of Christ was the the sign that should have brought all Israel to the Savior. Did that happen? No it did not. And as a result eventually Paul turned away from the Jews and focused on the Gentiles.
On one occasion, Paul was in a synagogue and he said he would minister to the Gentiles. But he went elsewhere and still preached to the Jews. Consider when he went to Rome.
As for Christians today, the basic principle is this: THE JUST SHALL LIVE BY FAITH. As for unbelievers in the world today THE GOSPEL IS THE POWER OF GOD UNTO SALVATION. Which means that the period of signs, wonders, and miracles from God through men is over. However, God still does miracles in answer to "the prayer of faith".
The gospel was the power of God unto salvation in the first century when Paul was working miracles, also. Paul wrote that the Gospel is the power of God unto salvation in Romans 1, and he also wrote in that book that from Jerusalem round about unto Illyricum, with signs and wonders, he had fully preached the Gospel of Christ. In I Corinthians he wrote on a similar theme-- God had chosen the foolishness of preaching to save them that believe, and to them that believe, Christ the power of God and Christ the wisdom of God. Then he wrote about believers in the body of Christ being gifted to do miracles. So you haven't presented a Biblical case for the idea that God doing miracles through men is over.
On the other hand, when the Antichrist appears he will come with SIGNS AND LYING WONDERS to deceive the world.
Jesus warned about false prophets in Matthew 7, about the fruit they bear, and that many would come to Him in that day, saying "Lord, Lord" telling about prophesying in His a name and doing many wonderful works. Then in chapter 23, we read that He would send forth prophets.
So from that early on, there was a promise of true prophets and a promise of false prophets. The same principal applies to miracles. The Bible does not teach that the genuine miracles were just for the past. I Corinthians 12 says the Spirit will gift one member of the body of Christ to prophecy, another with the working of miracles.... as He wills. The Bible never says the Spirit will no longer gift miracles workers. It is up to the Spirit to gift as He wills. You have no right to tell the Spirit of God not to do so, or to decree that He does not do so.