If these are the only options, fixed timeline. I reject multiverse theory on Occam's razor grounds. Dynamic timeline is logically unsound. However, fixed timeline (at least as presented in this graphic) seems to require a guiding force of some sort, which I would also reject on Occam's razor grounds.
Any theory of time first requires an explanation of the apparent broken symmetry of time ie. the so called "arrow of time". Sure, an entropic explanation is convenient but remember that the Second Law of Thermodynamics is statistical, not absolute, it leaves some unsettling questions unanswered in this context.
Not quite. Quantum mechanics says that fixed timeline is logically unsound. Dynamic timeline makes logical sense, however it implies the existence of multiple temporal dimensions. However, multiverse is already a valid theory in other contexts.
What do other people think? Which do you prefer?
Any theory of time first requires an explanation of the apparent broken symmetry of time ie. the so called "arrow of time". Sure, an entropic explanation is convenient but remember that the Second Law of Thermodynamics is statistical, not absolute, it leaves some unsettling questions unanswered in this context.