There's not any slider that controls the Mut 21 coins defensive line/backers that is why we have this issue. Right now, we can't possibly strike a balance in between the shedding and blocking.
On higher difficulties, this is a massive problem. All Madden player here, and can tell you STILL have not found the sweet spot with the penalizing sliders to make it realistic . That's 6 complete played seasons worth of analyzing mind you. Additionally, it makes getting tackles with linemen very demanding considering the only tackles you get are supporting the line if something. This brings up another issue, we need MORE SLIDERS.
The slider must do with sheds and shit. It's the same in 20. There is no slider which affects sheds handling the pass or run. It's only pass blocking and run blocking strength that we can tune. Too low, you constantly get by.
Honestly EA just seems like that they gave up on this one so that I doubt anything serious will get changed, but perhaps they're taking a look at pushing a lot of excellent features for your next gen version? I would hope that's true, differently buy Madden 21 coins is most likely the final one I'll play for the foreseeable future.
On the topic of players that are heavier, weight ought to Influence strength; I shouldn't have a NT that's 280lbs with 95 strength plugging the Inside of my line; it'd be nice to Have some type of hidden slider that affects the weight:intensity correlation.