Isn't it always the case when it comes to game adaptations of books and films? :D The books didn't feaure nearly as much combat as the games do, so if you wanted to make it accurate, you'd have to make a different game than an FPS, it'd rather be an adventure game or something. :D
I'd say 2033 is accurate enough, some details are different but the main events are there - the Dark Ones attacking VDNKh, Artyom going to Polis to ask for help, Rangers going to the Library to look for information about D6 and then finding the D6 itself (if I remember correctly, Artyom didn't go to D6 himself in the book, someone else went there "off-screen" to launch the missiles, but D6 is a pretty cool part of the game and it would be a shame omitting it) and then climbing up the Ostankino Tower to target the "nest" of the Dark Ones...it's there, with some liberties to make the gameplay more entertaining of course. :D
Some events from Metro Last Light actually happened in the book canon too, the Battle of D6 did happen, Miller also got maimed there (although he was also missing an arm in a book I think, and instead of getting prosthetic legs, he was using a wheelchair), some other characters died...we don't know the details and it's likely that it was different, but...most of the events from Last Light could've happened around the time Metro 2034 was taking place. :D
Metro Exodus is a lot different than Metro 2035, that's true. The idea of Artyom "searching for the truth" and Moscow being blocked from the outside world by signal jammers was present in the book though. And in the book, Artyom and Anna also left Moscow in the end, although they used a car rather than a train and it was only them. However, similar events could still unfold in the book canon if Metro Exodus took place AFTER the events of Metro 2035, just with the beginning being different (maybe there would be some other reason the Invisible Watchers would want to get rid of Miller and the Rangers, so they'd be forced to flee Moscow using a stolen train).
Overall, I'm fine with the portayal of the Metro world in both canons, it's similar enough to me. And it would be cool if a new book was released which would include some events from Metro Exodus. :D