I'm surprised to read that, as the movie is based on Liu Cixin's book. I haven't read "Wandering Earth", but I'm partway through "The Three Body Problem", and it's pretty hard sci-fi.
Yeah, the unscientific-ness of it bothered me. You cannot use 10,000 engines planted on one side of the earth to push it out of orbit and fly it into another solar system on a 2,500 year journey. There are so many things wrong with that. Even assuming that tech has evolved to a point where you can generate enough thrust, what fuel are you feeding these tremendous engines with ravenous no doubt consumption rates for 2,500 years? It can't be solar because we're leaving the sun. What speed are you moving the planet at? At a certain rate, the atmosphere will be lost and the nearest star (not the one that can sustain us, but the nearest star) is Alpha Centauri at over 4 light-years away. Then of course the largest problem is that no one can possibly survive on an earth hurdling through space without the support of a sun. Everything would be frozen solid all the way through including the underground cities that the movie says are supposed to be sustained by the heat of the earth's core.
But aside from that, the people-to-people interactions.themes are quite nice and the last part very inspiring.