so you are saying that in hollow knight there is a slight delay between letting go the button and stopping ,
I did just start up hollow knight to prove this , and it is not correct there is no delay in hollow knight .
the only thing there is is a slight animation pushing a bit forward and puling back again but the position of the knight doesnt change .
this is a very neat detail in hollow knight , the game is full of this stuff and to reach such a high level of polish as hollow knight has is a dream every game dev has
to your problem with lateral movement :
this should't happen , it isn't disabled or something and should work perfectly fine , maybe it has to do something with pressing to many keys at the same time on your keyboard. I had this problem once with a cheap keyboard where I couldn't use WASD and the arrow keys at the same time , maybe test if this is the case.
and yes the enemies are not processing while not on screen , I will make the range of this trigger a bit bigger , so it isn't as awkward :)
thank you a lot for taking the time to play my game and writing a comment