The cloud flats on the outside are my adjustment because they cover up the corner and out routes that you'd have to take with your user when trying to play Mable. This adjustment doesn't run afoul of "traditional" cover 3 rules because that cloud flat stays as deep as the deepest receiver like 90% of the time against a random bunch/trips play.
There can be reasons you don't want to always use cloud flats, especially against users who can hot route and motion, or maybe the AI is hitting you with one of the few stock plays that can beat a cloud flat to the appropriate side deep. Obviously against open trips you have to worry about the deep sideline to the trips side all the time, as opposed to bunch where you do not. Sometimes you need to use your knowledge of the game and its playbooks to help compensate for Madden's simplistic defenses. Think of this as the result of "film study" if you need the pretense of realism.
So instead we're just going to play a regular cover 3 with hard flats. You can call it in the huddle or you can make it out of hot routes. This time our user will be the strong side MLB instead of the weak side MLB.
The basic idea would be to play any vertical release from the #2 receiver to the trips side and then cover him 1 on 1 on any out breaking routes that won't get picked up by the hard flat. There's no one to cover him if he runs a 10+ yard out or a corner, so you'll have to take it. Don't worry about nuisance routes like the slant hook from Z Spot. It's fine to concede the short completion in most situations if you can make the tackle right away.
In a stock cover 3 you'll have help on any in breaking or deep routes, so you only have to stay with those long enough to pass them off. You can then either return to your zone or go looking for work if the offense isn't threatening that part of the field.
For example, if the offense runs a drive concept you'll stick with the in route through it's vertical stem and just long enough once he cuts to let the other LB take him. Once that happens you attack the drag.