If you don't mind, could you explain what you meant by the Promised Neverland anime being different genre or route from the manga? If I (mostly) like the anime so far, do you think I'd like the manga too (after the show is over)? Or are there a ton of differences so far?
I would say the manga is more focused on psychological genre and mind games while the anime is more on the horror/suspense side. The characters motivations are more explored in the manga too, and you might have heard this a lot, but the anime doesn't have internal monologue so the intentions are muddled (it is making things fresh and interesting though, so I personally would not complain about it), but I think by the end of the cour, it'll come together.
A different "route" is not saying that the anime is changing direction from the manga or anything, is just I don't really know how to describe the word properly and "route" is the best thing I could write at the time. A different approach is more appropriate, I think.
The first arc of TPN is about breaking out of the farm, and the 2nd arc is more on survival (bear in mind the cour might not cover the entire 1st arc or it might go to the second, who knows ¯\_(ツ)_/¯). If you expect everything will be the same, I think you'll be disappointed. But if you're invested in knowing the world more and the journey of the characters, I think you'll like it!
There're quite a few differences in the anime and manga, but the anime is taking its time to make a different identity and making use of its medium. And my gripes with it are pretty small and at best nitpicking.
But if you do want to start reading the manga, I still would suggest reading from the beginning, there is a few side scenes that is funny and making you more invested in the characters and well... there's some pages or chapters that didn't make it to the anime.
Please support the TPN anime (and manga, if you do read it when the anime finished airing/can't stand the cliffhanger anymore) from now on!