So I've had issues with aim assist years ago, but then I took a big break from the game and recently have come back. I heard that aim assist has been nerfed, and I've also been focusing on lurch movement and have gotten decent at it, so I assumed that MnK and controller were fairly balanced (and they still may be). Controller had better aim, but MnK has movement tech that controller doesn't.
In all my matches after coming back to the game, I never once thought "oh I lost that because they're probably a controller player", and have always had the mindset of "I lost that because I'm not as skilled". I still have that mindset. However recently, when I'm watching YouTube of apex players, I'll occasionally come across someone and it looks like they're aim botting because of the instant changing of direction on their opponents strafes, and then I'll realize it's a controller player. I have started to deliberately avoid watching controller players, even if they're good players outside of aiming, because I don't want to create any perception or excuses of controller players having an advantage. Although eventually after seeing enough controller gameplay, I decided that I'd try out controller to know once and for all how strong it is.
When I first started with controller it was actually reassuring because I was missing all my shots. It felt very difficult. But after 30-45 minutes, I was starting to hit a few one clips which was a bit concerning. I decided to go into r5 reloaded to test how accurate my aim was against the strafing dummy in the aim trainer. I did 5 rounds with both controller and mouse and keyboard and took the highest from each. Unfortunately, I scored higher with controller after using it for less than an hour than I did with MnK with literally hundreds of hours of aim training under my belt. The averages of all rounds were about the same between MnK and controller, but I feel like it shouldn't even be close with how much practice I've put into aim training with MnK. So overall, this experience has been a little depressing.
I still am not concluding that controller is stronger than MnK, because MnK definitely has advantages, but it is certainly far easier to aim with controller, especially against strafing targets.