This is like saying “If Bank Balance is everything, then what is the use of earning”
What is fate, if not ACCUMULATED KARMA?
Nature gives us our fate based upon our karma from the past several lifetimes. That’s your opening balance for this life.
It also gives us free will to add or deplete the balance by doing our Karma.
Some things are fixed e.g. the family you are born into, the nation, the parents you have etc. That’s called Prarabdha Karma (fixed destiny)
However other Karmas can be worked out. E.g. if you work really hard, at least you won’t starve to death in most cases. I often tell people with Bad Money yogas to donate as much as they can and open savings accounts in the name of family members.
I have often seen childless couples being blessed after serving orphans and best remedy in such cases is to adopt an orphaned child. So on and so forth.
So the more you can literally make or break your own fate.