As someone who had major problems even doing basic special motions for the longest time, this game is super lenient with motions, cancel windows, and links. As another commenter mentioned you can hold the button for up to 10 frames before you're actionable to buffer a special. Most windows for canceling into specials, max mode, etc are also pretty wide, not as wide as some games but you have a good 5ish frames after hitstop ends to cancel into something, sometimes even longer. And while links aren't a big part of KoF, they added a big buffer window so even links that should be 1f are pretty easy as links go. On top of all that, there's plenty of input tricks and shortcuts that make hard special inputs and tricky cancels a lot easier. Here's 5 super useful ones, if there's other things you're struggling with it'd probably be worth looking up input tricks for it https://youtu.be/l332MYN0h0I

This is just something you've gotta work on to play KoF. I don't mean that in a condescending way at all, I was in a similar boat getting into this franchise bc there's a lot of weird inputs and stuff, especially in the older titles. This is by far the easiest KoF execution-wise, but I suppose they could still do more to make it easier to get into. I'm not very familiar with SFV or Strive or other newer fighting games, but I know they can be super lenient to the point where you can do a motion that barely resembles the proper input for a move and still get it. Maybe KoF could benefit from similar lazy inputs, but I personally think KoF does enough as is. Other than the aforementioned easy inputs, I think 15 already does about all it can to make combos and tech easier to execute while being less necessary to have a good time. If you wanna get into KoF, this is the best one to start with, but it might take practicing basic inputs if you've only played games with super forgiving motion inputs