I think that all the events of the world are just the results of the
application of the rules of nature on the previous situation of the
world.
I agree with you Dvij, I can tell you are sincere in your search for truth and I myself came to a very similar point in my life. This is why I am going to try my best to give you the answer I have found for this problem.
I agree with you that results from a moment of action/inaction are determined by the laws/rules governing nature. I also agree that this applies to every moment of action/inaction. We can call a moment of action/inaction by a different name, "the previous situation", because that was the state of the world that was changed into the resulting state of the world by that action/inaction. In other words, a "previous situation" is indeed what caused the resulting state of the world/reality, because it is made of two elements: the previous state of the world and the action/inaction that changed it.
However, even if we didn't have a choice about what the previous state of the world was, we still definitely had free will when it comes to the action/inaction that we took and that resulted in the next state of the world (with the exception perhaps of some mental illnesses which might completely or partially dictate a person's actions, but I'll ignore those in this answer due to their low incidence/prevalence in the population). This free will is evidenced by the great sense of freedom we have right now about getting up from our chairs and jumping out of a window, laying on the floor shouting, going outside and jumping over the neighbor's fence, studying hard for an exam, or doing a cartwheel into the bathtub. We can decide to do any of those things right now, and every moment of our lives we have many things we can do. We decide, and that is free will. There are many things we can't do, like teleporting to a friend's house, traveling back in time 20 years, or turning rocks to gold; but the reason for that is not that we don't have free will, it's that it's impossible to us.
Therefore free will is the ability to decide what to do between the things that are possible for us. Because of this, it is true that the events of the world are just the results of the application of the rules of nature on the previous situation of the world (which is comprised of the previous state of the world and what we decided to do/not do with our free will at the time).
Our thoughts or efforts are also completely predetermined.
The events of the world are not predetermined, as shown above, they are what we do with the world around us by using our free will to decide between things that are possible for us. In the same manner, our thoughts are mostly common/usual responses that each individual's brain has as a result of repetition. We can slowly change the way we think, as well as the nature of our thoughts; this means that we have some measure of free will even in our thoughts. Our effort is the amount of work/energy we decide to apply to something; and if we had some measure of free will when it came to our thoughts, we have all of it when it comes to the amount of effort we decide to apply to something.
If this is true then there remains no meaning of moral values such as
success, defeat, winning and so on.
Perhaps, or perhaps not; luckily for us that is not the case because it is not true (as shown above). However, even if it were true, there might still be some intrinsic worth to moral values. Success, defeat, and winning are not moral values; but they would certainly have no meaning if hard-determinism were true.
Our efforts also don't matter to any large extent because they have
been pre determined.
Our efforts have not been predetermined, as shown above, but the importance of our efforts lies in that they strongly influence the likelihood of success in what we apply them to. I honestly hope this aids you in your quest for truth.