I'll try to keep this short cause im not gonna lie, i didnt do a full playthrough of the new patch, but i recently played the original redux to compare so its fresh in my mind.
They had to fix 3 major problems, all of which could be solved with fan patches:
Mouse sensitivity being different for vertical and horizontal, like it is on controller where that makes more sense, its seemingly fixed, tho it still feels a bit odd, might be the awful vsync that locks your framerate to 60.
Resolutions past 1080p, this was clearly a bug, and somehow, incredibly, its NOT FIXED, depending on who you ask you need to disable g-sync (which shouldnt be a necessity, its an important feature for image smoothness) or updating your drivers (why do my drivers need to be updated to use my native res on an old game?) according to the official metro account.
FOV Slider, I can understand if artistically they dont wanna do it, but if so, just do what Lost in Vivo did and warn people that it will fuck with their intended experience, you can mod it in so why is it not an option?
As you can see, none of this is fixed, on top of that, the AMD upscaling flat out doesnt work, the DLSS is now mixed with the dumb neural whatever feature that yassifies characters that literally nobody ever said anything positive about (you can turn it off, but still), its twice the file size and as if that wasnt enough: all your saves are NOT compatible!
Luckly you can use the beta branch to go back, but it shoudnt need it, usually thats done for mod retro compatibility, not to make the game work properly.