If you define luck to be exactly synonymous with chance, then you are right.
There is a subtle difference between luck and chance. Chance is that uncontrollable randomness. Luck is a combination of chance, being prepared, noticing opportunities, not dwelling on negative experiences, and increasing entropy.
If you look at luck as a combination of those factors, it turns out most are under some degree of your control.
I know plenty of people who have decent lives, are lazy, keep a strict routine to minimize surprises, and have not reacted to opportunities which could have turned out really well for them. They consider themselves unlucky.
You can be prepared for opportunities, and you should. Prepared people will, on average, fare better than those who are unprepared.
But there are a trillion factors beyond your control. Smart, prepared people fail all the time. Stupid people randomly succeed all the time. The former group will do slightly better than the latter, but not nearly as much as you'd hope for from a just world.
I get exercised about this because it quickly leads to blaming people for misfortunes. If you can reliably make your own luck, then people who have not fared well must be stupid, lazy, or morally defective. That lets us get away with thinking that it couldn't be us, and that we don't need to have any compassion for them. That makes an unjust world even less just.
Yes, go do all of the things that you'd think of as "making your own luck". But spare a thought for the fact that while "luck" isn't magic, it is the result of factors that you cannot control and aren't even aware of. That's healthier for you and healthier for society.