I apologize for the question of someone who knows little and understands little. Why evaluate the consumer property of the output file based on graphs and numbers? 99% of people will not see any difference in the video after different codecs, which has been confirmed repeatedly, just by a survey of viewers.

Why should Vegas be able to read ALL the videos shot by DIFFERENT devices, of which there are a great many types and different settings, correct and not so? A long time ago, for example, editing codecs were invented that turn different input into understandable and processed video. Vegas, this is an assembly program, not a harvester. Let her mount well, and preparing source videos from a huge number of input formats is not really her business.
I apologize for the long post. 
IMHO

Sometimes it is strange to read the questions of people who work (according to them) professionally, and in a professional video editor, but do not know how to prepare a raw video to work in the program. Once again, I'm sorry.