Can you please share more about this? I haven't seen any credible contradictions among the Gospels - but I keep hearing credible people reference it.
If you want to study the differences between the gospels you may use a so-called "synopsis", that presents equivalent text passages from the different gospels next to each other. For example this color-coded one, that make it easy to spot differences: https://sites.google.com/view/biblestudyresources/gospels/co...
Another interesting difference in the New Testament concerns the text of the Acts of the Apostles. To quote from Wikipedia: "There are two major textual variants of Acts, the Western text-type and the Alexandrian. The oldest complete Alexandrian manuscripts date from the 4th century and the oldest Western ones from the 6th, with fragments and citations going back to the 3rd. Western texts of Acts are 6.2–8.4% longer than Alexandrian texts, the additions tending to enhance the Jewish rejection of the Messiah and the role of the Holy Spirit, in ways that are stylistically different from the rest of Acts." -- https://en.wikipedia.org/wiki/Acts_of_the_Apostles#Manuscrip...
Include 3 specific women in the list.
List non Jewish heritage -and the specific number of "jewish" relatives necessary to make Jesus a "full blooded jew". This is important as it reflects the Jewish nature of the authorship of Matthew
Having different versions of the Lord's prayer isn't a problem either. Perhaps one author didn't find the entire prayer important enough. Or didn't find it important enough to include at all. This is what you would expect if 4 friends were writing down a single event they all attended.
The same goes for differences in the death and resurrection. In fact some of the differences are explained by the different background of the authors - which you would expectif there are different authors.
Also, two versions of Acts that are different by 8.4%? Really? Does it change the gospel? If not, then does it matter?
This observation allows us to conclude with high confidence that this passages constitute a "hidden" intependant gospel, that Luke and Matthew used together with Mark (and their individal traditions).[1] And we have also a very early Christian example of this literary genre of a collection of sayings ("Logiensammlung") in the (non-cannonical) Coptic Gospel of Thomas.[2]
Another remark in this context: That the different gospels (including, but not limited to those that become later cannonical) contradict each other one way or the other was noticed very early. There had been an attempt to construct a single sanitized gosple by Marcion of Sinope around 130-150, which was more or less a condensed version of Luke. It is interesting that such an attempt to propagate a single gosple as the only binding one was strongly opposed by many and resulted in a canonization of a multitude of four gospels and the popularity of many others for centuries. This diversity of "witnesses", characteristic for especially early Christianity stands in strong contrast to the historically rather naive biblical literalism (biblicism) of 19th century to contemporary Evangelicals.
[1] This was only a very brief summary, neglecting a lot of the scholarly discussion around it. For a somewhat more detailed introduction you may have a look at the Wikipedia article: https://en.wikipedia.org/wiki/Q_source
[2] See: https://en.wikipedia.org/wiki/Gospel_of_Thomas