Time travel

I have been putting off writing about time travel for a long time since there is no real proof of how it works or if it exist. But I have had time travel and timelines on my mind since I as a little kid saw my first time travel movie. And I have been thinking about it a lot trying to find the logic in how it works. Also I do not have a relevant degree in this field but I have seen enough movies and series to think I know something about it.
To start it if off we need to understand how the timeline works. As I see it there are three ways to view time. The first is "here and now" there is no past or future, there is only here and now. This eliminates time travel as there is nothing ells to travel to. Everything there was and everything there will be is just an illusion. This though seem unlikely as we collectively are sure that the past have been there, that it have existed. We write books about the past so it must have been there.
Which leads to the second way of viewing time. We know from the laws of Thermodynamics that energy can not be destroyed or created. So if the past exist a future must also exist or we would just create more past from nothing. So the second way of viewing time is as a singular timeline with only one past and only one future. Everything that will happen in the future is preplanned and we can not change it. This eliminates free will. No matter what we do it was destined to happen.
The third way to view the timeline is through multiple timelines. Every choice made is a choice between different possible timelines. This means that there are several millions possible futures just for a single person and our entire universe together choose which future we move towards. But our choices does not create "new" timelines for that would break the laws of Thermodynamics. Every possible future exist simultaneously we only choose between the different paths. The best way to really imagine this is to think of the entire universe's timeline is one giant tree with nearly infinite branches on it and every single branch is a possible timeline.

So if someone were to travel through time they would either experience absolutely nothing as there is only now. Or they would travel to one definitive future with no possible way to get another and no possible way to change the past as it is all pre set. Or you would travel to just one of the many possible futures and changing something in the past would not change your original timeline. It would only be you travelling down a different timeline.
This is where many movies and TV-series mix it up. They portray time as a singular timeline where everything that will happen has happened but also give the possibility to alter time. So a person would travel back in time to alter the future. But since the past and future is set. The time travel would have happened and influenced time to make the timeline the person is currently living in. So the person does what would already have happened but changes the future so the person does not have to travel back and therefore creating a paradox. This is illogical for something can not have happened and not happened at the same time.
What should happen is that the person travelling back in time would change something and then the person travels back to the future. The person should either return to his/her original timeline where nothing has changed for what the person did was just "opening" a future for an alternate version of him/her. Or the person would travel down the timeline "opened" by the changes he/she did and end up in an alternate future. This future is not the person's old future that have been altered but an entirely alternate future where and alternate version of the person lives or lived depending on whether he/she died or not. So if the person arrives at the alternate future he/she would own nothing and have no friends or loved ones, it would all belong to his/her alternate version. And the timeline the person travelled back in time to change would stay the same. Everything he/she tried to save and change would still be in danger. But his/her existence in the alternate timeline is "opening" another timeline.
To try and explain it a little further, let us say I travel back in time. Misguided by TV I bring something to confirm that what I do changes my future. The moment I travel back in time I split my timeline in two; one where I travel back in time and one where I do not. When I arrive in my past, let us say I arrive in 1995, I am not actually arriving in the past on my timeline but an alternative timeline. For there was only one of me back in 1995 on my timeline. The timeline I arrive to is the alternative timeline where there for a period is two of me; one as a baby and one from a different timelines future. So now that I am in the past, thinking it is my past, I kill those people starting the even I am trying to prevent and every time I kill someone I check on my timelines future to see if it has made a change. But no matter how many people I kill on this timeline, my future will not change, for it is on a different timeline. At some point I will try to travel back to the future to see for myself if all I have done made a different or not. But I will be travelling along the time of this alternative timeline. So instead of arriving at my future, I will arrive at an alternative future. A future that is different from mine in many ways. And everything I own and everyone I know would be different people. And there would possibly be a now grown up alternative me. If I were to return to my own timeline, maybe there simply was a return home button (that will be smart to have). I would arrive back at the timeline from where I travelled back in time and it would not have changed in any way. It would be exactly like I left it and it would only be me who had changed during my travels.
And it annoys me immensely that no movie or TV-series (that I so far know of) gets it. They all go into the same illogical plot where the person creates a paradox where they try to change the future that they would already have been a part of. I understand that it makes a more dramatic plot that the person have everything to lose when trying make a better future for his/her family. But for once I would like plot where a person think they can get back and change the timeline only to find out they end up on an alternate timeline and has to figure out a way to get back home to his family and then learn that everything is the same for he/she never changed the future just chose different paths.