Major for best chances of getting into UCLA

I am looking to major in the field of business, but the business economics major at UCLA is one of the most popular. Do I have less of a chance to get in because it is so impacted? Would this be a major factor in me not getting admitted?

If it’s in letters and sciences, couldn’t you apply undeclared and decide six months in?

Im applying to UCLA too, but to the school of Theater, Film, and Television, so my issues are completely different.