Guys, thanks a lot for your guidance!
I have X1C just for few days, so I was getting used to X1C approach.
I visited this page, there I understood how the startup G-code procedures are handled in Bambu Studio.
Then I created a test object to print, then I studied generated G-code, identified moments of unwanted prime lines creation and here is the result:
I have deactivated command lines in red rectangles (by means of “;” sign, to have a backup 
) in Machine start G-code and that’s it! All prime lines from the initial picture of this thread are gone!!! (Machine start G-code could be still optimized to save some “useless” moves, but at this moment I am happy 
