The copies we have all show songs of editing. Many are simple errands but there are some intentional changes. I tend to view a text as more fluid and unstable before it becomes popular and fixed in the tradition. There are plenty of indications the texts were somewhat fluid before the manuscript evidence. I layout some evidence here:
If you do some research you would see there is a dark period of well over 100 years with minimal information about what the New Testament looked like. Sure, there are thousands of copies but most are from a millennium later. How much of each of the NT works can you actually reconstruct from manuscripts the first 50 years? The first 100 years? The first 150 years?
Some scholars are more favorable to tradition 100 years after the fact. Some are more skeptical.