> These text came into being later without titles. They circulated without titles. Its later church fathers who just assigned names to them based on tradition.
As someone who was raised in the christian faith, learned the sunday school version of the bible and only later seriously studied the texts (first in theological seminary and later from a purely historical perspective after becoming an atheist) - it's remarkable how different the consensus of serious historians is from what most people learned in sunday school.
As you've said, we don't even know who wrote the synoptic gospels, where or when (closer than estimated decades). Due to the lack of original documents, reliable contemporaneous accounts and other supporting evidence, we know shockingly little with any certainty. It's extremely unlikely the authors of the gospels were eyewitnesses to any of the events they describe. I was most surprised when I learned from later study just how much the canonical bible I'd learned as a child was retconned hundreds of years later through an opaque process of curation and editing by fractious groups of church leaders at events like the Council of Nicea.
> In Mark for example, Jesus basically doesn't say that he is the son of god.
Which is why the many inconsistencies in today's canonical new testament are even more remarkable. This is the most consistent version they could assemble from a far larger group of even more divergent, inconsistent texts. Ultimately, the bible we know today is descended from a pastiche of copies of copies, written over decades by unknown authors in different places and languages and then survived several 'negotiated settlements' between opposing factions arguing over arcane theological points under an overarching power dynamic trying to unite some semblance of a unified "church" (and even what we know of these councils is only the sanitized version written by the 'winners').
Applying an adult's experience of how large groups work and how ad hoc organizations adapt orthodoxies over time and distance (ie 'telephone game'), the only way to not see the synoptic gospels as randomized fan fiction largely unrelated to any actual historical events is to believe that god miraculously intervened dozens of times over hundreds of years to force an historically "correct" bible to be the surviving version we know today.