is it gonna be a problem in the future if i just use \n everytime i wanna write a something new instead of cout<<"" everytime

Answer 1

i think the better way to go for a new line is
cout << "hey\nBye"; with \n
or cout << "hey" << endl << "bye"; with endl

Answer 2

There also a big advantage of endl over \n
cout<<endl ; is equivalent to
cout<<"\n"<<flush;
flush is used to clear buffer input.
that's why endl is very much used in working with file which is opened in binary mode.