does steins;gate make total sense?

this will contain spoilers.

Steins;gate is a good, entertaining show, and i would recommend it to everyone, but

time seems to function both linearly and with multiple dimensions (string theory).

Im pretty sure these 2 are mutually exclusive. Like going back in time shouldnt change your current timeline, it should merely create another, just like all his d-mails were doing.

Also even if we ignore that, i dont see how fooling his past self into thinking Kurisu Makise is dead would cause her not to die. I can see how it would lead to Okabe starting his whole d-mail experience, but if people are fated to die in certain timelines, then wouldnt kurisu still die?

and Okabe, he goes through timelines never realising that the only person who's life will change is his own, wont all the other timelines still exist where people die, wars happen, or sterns takes over. He's not trully saving anyone. Isn't he just trying to find a timeline that works in his favor? (Makisa kind of mentions this to him near the end, which made me glad, because i was wondering how no one had addressed it prior to that). Like Makise and Mayuri are gonna survive in like an infinite amount of other timelines anyway and die in an infinite amount of them too no matter what Okabe does.

i find some stuff doesnt make a lot of sense, at least to me anyway. This is just a couple things ive thought of, what do you guys think. Maybe you can explain this, or have you noticed other things?