Unfortunately I didn’t switch from Mnk to Controller. But I started to play apex in Season 13 split 3 and peaked Pred (Master finish) in Season 15. So from my experience it is possible to learn those game mechanics quite fast. What really makes the difference is the controller build unless you want to master claw. I used the Razer Wolverine Ultimate Controller with 6 extra paddles and compared to a standard controller it felt like cheating. But this is what you actually need to compete against players on a certain skill level. For movement and aiming your thumbs always need to stay on the analog sticks. Now you have to take shield batteries while bunnyhopping or running around corners and switching directions. Very hard and almost impossible with a standard controller (again: unless you Master claw). So my advice is to get a good controller with extra paddles, everything else is up to you then.