After Effects CC2018 won't let me reassign keys in custom keyboard window

It is 2023 and I am trying After Effects for the first time and I am asking my After Effects why R is such a special key that I must not be allowed to assign it to 'rotate' instead of 'bring up rotate parameters' or whatever the default is. And it is not telling me why. And all I can find on the internet is this thread, that reports that ten letters of the alphabet are not available to reassign.

Why, Adobe? Why are these function blessed, and unchangeable from whatever your developers think is the best way to use this complex power tool? I do not know. And I am pondering the effort involved in learning enough of this program to truly understand why these choices have been made, keeping in mind the fact that my intent to try to marry it to Illustrator as an animation tool and might be wholly *incompatible* with the way the developers expected their program to be used, versus the effort involved in learning a Grease Pencil animation workflow in Blender, and Blender is looking really, really competitive here. Blender is also a massive, powerful pile of UI decisions made by people who are not me, and I am sure I will be saying "why, Blender, why did you assign this action to THIS key" many times as I play with it, but at least it will let me *change* a lot of them.

While Szalam's answer has been MARKED as correct, it's not technically correct. There is a way to do this, which I posted on Uservoice: https://adobe-video.uservoice.com/forums/911311-after-effects/suggestions/38385004-remove-keybind-restrictions

But I'll post it again, here.

You can circumvent the keybind restrictions by modifying the .txt file the keyboard shortcuts are saved to.

For me, the folder location was here:
C:\Users\13gpu\AppData\Roaming\Adobe\After Effects\16.1\aeks
You'll have to replace "13gpu" with your own username.

And my current text file of shortcuts is called:
taran 4 - AE keyboard.txt
...but yours will be different.

Then I just opened that file in a notepad, and changed a few lines, like so:

Then I saved the .txt file and restarted After Effects. It works like a treat!

Why suddenly make it more difficult to customise AE? That doesn't make any sense!!!

Today I found out that I can no longer use the shortcut keys I've had assigned for over six years!!! Adobe, whyyyyy??????

I've always had D as one frame back and F as one frame forward, and Shift & D as ten frames back, Shift & F as ten frames forward. With my right hand on the mouse, these keys sit absolutely perfectly where my left hand rests on the keyboard and makes moving incrementally through the timeline super-ergonomic and fast.

Using the default Command & Left/Right Arrow keys seems silly, because I have to hold down Command with my left hand and then  take my right hand off the mouse to press the Arrow keys. Doesn't sound like too much of a hassle but if you're doing that all day, when you could be just pressing one key, it's just a massive waste of time and the complete opposite of ergonomic.

Please just let us assign what keys we want where we want. And especially don't make things we've used for years suddenly unaccessible. That is soooooo annoying!!!

Sorry for bitching but locking that F key has completely ruined a workflow I've been using for years.

Change it back please!

Sorry my bad. It just worked after I deleted old shortcut for the "O" key which was the in point function.