I agree. And it is more complicated than the question implies as the text we now have available to us is undoubtedly the result of many authors.
While we tend to consider there to be a single author and a single point in time (usually about 80-90CE), this is simplistic. Firstly scholarly analysis suggests that there may be multiple sources for the gospels prior to their 'writing'.
I agree. Harold Riley has found within the text of Canonical Matthew, what he calls 'proto Matthew', to which has been added other material, which he identifies by looking for signs of interruption in the narrative. For example, Matthew 9:27-34 has the healing of two blind men, and then a mute spirit is driven out from another man. Riley says that these two incidents are doublets of Matthew 20:29-34 and 12:22-24, the latter two being embedded in the original narrative.
So it looks like 9:27-34 is a later addition. (There is more evidence for this. The section in chapter 9 before the miracles involving blindness and demon possession, which is the raising of Jairus' daughter, makes a fitting climax for a larger section, 4:12-9:26, which expounds the author's quote from Isaiah 9 in Mt 4:14-16. The quote finishes with "on those living in the land of the shadow of death, a light has dawned").
But as significant is the timeline from their original version (which we do not have) to the versions we do have, typically from hundreds of years after their claimed original date. These later version is what we know as the gospel and will have had many 'hands' involved - for example in accurate or inaccurate copying, and more active editing through the decades that may have resulted in chunks being changed, added or deleted.
In the context of the sections containing the call of Matthew and the list of the disciples, the three Synoptics are similar in format and wording, indicating a degree of copying between them. But as you say, alterations have been made by later copyists. For example, Matthew 9:13 has "I have not come to call the righteous, but sinners". Textus Receptus and Byzantine have "but sinners, to repentance" which is in Luke's version but not Mark's. It looks as if "to repentance" has been added into Matthew by TR and Byz due to a recollection of Luke.
So what we actually have - and what we would now consider to be orthodox gospel text - is in fact the product of writing, editing, curating etc etc by many people over hundreds of years. And importantly what was considered to be 'orthodox' or otherwise is effectively a political decision by the early church in about the 4thC.
Equally the original texts can to a large extent, it seems, be deduced through analysis.