I hear some Christians saying that the gentiles took over Christianity and made it less Jewish.
I disagree but I want to hear your opinion.
I've heard a number of testimonies about Jews who have become believers in Messiah and one of the things that was commonly mentioned upon reading the NT for the first time was that they were shocked to see how Jewish it was. Jesus did not come to start his own religion following a different god, but rather he was born a Jew, raised a Jew, became a Jewish rabbi, had Jewish disciples, fulfilled Jewish prophecy, and came to bring fullness to Judaism as it Jewish Messiah. Jesus was sinless, so he set a perfect example of how to practice Judaism by keeping all of its laws, and as his followers we are told to follow his example (1 Peter 2:21-22). The goal of a disciple was to learn from their rabbi how to walk out the Torah by memorizing their teachings and by imitating their actions, so that is what Jesus taught to his disciples, and we are told to walk in the same way he walked (1 John 2:1-6) and to be imitators of him (1 Corinthians 11:1). All of the books of the NT were written by Jews and all Christians were Torah observant Jews for roughly the first 7-15 years after Messiah's resurrection up until the inclusion of Gentiles in Acts 10, so Christianity at its origin was a sect of Judaism.
However tensions between Christians and non-believing Jews caused them to polarize over time, with Judaism becoming those Jews who followed the Torah, but rejected their Messiah, with Christianity becoming those who followed Christ, but not the Torah he followed, and with both following only half the truth. The Torah is the way (
Deuteronomy 10:11-12, Psalm 119:1,
Jeremiah 6:16-19), the truth (Psalm 119:142, Psalm 19:7,
Nehemiah 9:13), and the life (
Deuteronomy 30:15-16,
Proverbs 3:18,
Matthew 19:17), Jesus is the way, the truth, and the life (
John 14:6), the Torah is God's Word and and Jesus is God's Word made flesh, so they are the same way, truth, and life, and there is no following one apart from following the other.
I have an acquaintance who went to seminary who told me that if they had told him that Jesus was Jewish, then that would have completely changed his outlook on the Bible. So today Jesus is often treated like he was a white European Gentile and many are surprised to find out he was Jewish and most likely didn't look anything like his painting, so I would certainly agree the statement in the OP. The way that those who grew up in Judaism understand the NT is different than from how Gentiles understand it because they tend to have a much better understanding its Jewish cultural and historical context, so I there is much depth of understanding of the Bible that can be gained by studying it through this perspective.
For example, the understanding that many people have of the Pharisees is limited to only what is recorded about them in the Bible, so without background knowledge they are lacking a good understanding who they were, what they were about, and why Jesus had such as big problem with them. We have the stated position of the Pharisees and of Jesus, but what most Christians are lacking is the position of what Judaism of that day taught on that topic. For instance, Jesus could have argued with the Pharisees by quoting Rabbi Yehudah as saying that his disciples were permitted to crush grains of wheat with their hands on the Sabbath as long as they didn't use a tool, or by quoting Rabbi Yehudah as saying that washing hands before eating a meal is optional, but instead of debating matters of halakhah, Jesus always went to the heart of the matter.