Mapping keyboard key to controller - will this negate aim assist?

Hi,

I'm writing because I'd like to better understand a specific aspect of how aim assist works on PC; my ultimate goal is to map a keyboard key to one button on my controller, and I want to make sure this won't somehow negate controller aim assist.

Initial problem

I'm learning how to use "hold-to-crouch," as my new controller has paddles and having hold-to-crouch on a paddle provides extra mobility. However, there's a catch - with hold-to-crouch, it's not possible to crouch while using certain items, like the Respawn Beacon. This is a fairly significant limitation. On keyboard, this is not an issue because you can have two separate crouch buttons, but on controller you can only have one or the other.

To remedy this, I'm planning to map a keyboard key to my B button, so that I can have toggle crouch on B, and hold-to-crouch on a paddle. When I push the B button on my controller, it will send a keyboard key which will correspond to my keyboard controls toggle-crouch.

The aim assist question

In Apex matches, you can switch inputs on the fly. This means that I can play with a controller all game, and then pick up my mouse at any point during the game and start using that. My question is, when this happens, does Apex disable aim assist immediately? My understanding is that controller and mouse have different aim assist levels, where mouse is not allowed to have as much aim assist as controller. If I push a keyboard key, could this cause Apex to think I'm using KBM and disable my aim assist? How does the transition from controller aim assist to mouse aim assist work? When does it change from one to the other, and when does it change back? 

Thanks for your help.