How to switch players on defense during play?

Can someone please explain how to switch players on defense during the play? I'm playing on PC using my Keyboard only. In the settings, the button F is foreseen for switching players (although I have no idea why F is foreseen for both "Switch Players" and "Speed Rush"...?? see screenshot below).

In previous Madden versions I could press F and I switched to the player closest to the ball (or the DB closest to the intended target during passes). In Madden 26 it seems to be completely random. For instance, I play the defender covering the HB in MC and blitz if the HB is assigned to pass blocking. When I want to switch to another player (pressing F) I often end up anywhere at a random DB although no pass is thrown. Sometimes I switch to the defender closest to the QB (who still has the ball). I've also tried to see if it's because I'm pressing the arrow keys, which I use to set the direction, incorrectly. But that makes no difference (if I got it right, a mechanism has been introduced that makes it easier to switch between DBs, but I'd guess you need a controller to do this?).

I'm not sure if I should even try switching players, because if I don't know where I'm going to end up, I constantly make mistakes and take out the defender I'm switching to. I don't even want to know how many TDs I've received just because I reacted completely wrong again, because I didn't switch to the player I expected.

What am I not understanding here?