RNH and Bouchard disappear in any physical game, that's called being a coward. You haven't watched Michael Nylander if you think he has more tenacity than his son.
But if you want a list of multiple seasons I'll be glad to give you one: Phil Kessel, Johnny Gaudreau, Jonathan Huberdeau, H and D Sedin , Patrick Kane, Patrik "Loser" Marleau, Hughes Trio. So yea, there are many many players. Hell Marner is just as soft if not softer than him, and Matthews hates touching other players.
Moving on, you do know that being able to score goals and make plays is also important to playoff hockey, and is bigger than why we have lost in the playoffs every year. You can't defend a lead if you don't have one. Since entering the league he has 40 in 50, since signing his contract he has 32 in 37, since breaking out he has 29 in 30. Those are the stats that matter the most, and Ideally he does even better as the playoffs come.
On the last goal....he stood in his position, was his stick facing the wrong way? probably, but he in no way should've been covernig draisaitl especially in "man to man" when edmonton has 6 guys....is he supposed to guard two people? No he collapsed to the middle so if the puck goes back to bouchard or ekholm, hes in the way for a potential block.
That's not to mention that entire play has nothing to do with "being a coward", unless making a mistake is being a coward. In that case, Mcdavid is just as big if not a bigger coward for that second McMann goal because not only was he standing around, but he was also lazy at 5 on 5. Moreover, if samsonov stops a puck sliding across the ice, none of that matters but whatever, or if knies doesn't lose another board battle.
in terms of man-to-man, he and tavares held mcdavid and draisaitl to 0 points and outscored them 2-0 at 5v5. So I along with many others think he did very well 5 on 5 man coverage.
So which one is he "cowardly" or bad defensively? You mix both of them up and seem to confuse yourself. The former has no basis, especially compared to his teammates and others who've come before. The latter has an arguement to be made, but it's significance is overrated a lot of the time
Edit: LOL what couldn't back up your claim?