A lot of people believe that "you get what you pay for", the implication being that expensive things will be good or best and cheap (or free) must be inferior or poor.
In many cases that belief is incorrect!
iMovie is an excellent video editing app which will enable you to make the highest quality films.
Final Cut Pro has certain extra features which are only really necessary for professional studios working with teams of collaborating editors.
In most cases, iMovie has more features than most users will ever require. FCP is overkill.
We frequently receive claims that a certain person cannot make good films because they only have iMovie.
Rubbish! They can't make good films because they themselves are no good at making films.
Bad workmen always blame their tools and in most cases their films would be just as bad whether they used FCP or any other expensive editing app.
iMovie is NOT a "second best" or inferior choice. It should be first choice for most amateur editors and a few professionals as well.
https:/www.apple.com/imovie