The foul is irrelevant if it’s offside so the refs/VAR wouldn’t do anything.
For retrospective punishment they’d have to believe Pickford deliberately did it which I don’t think he did for the reasons I detailed. He just threw his body in the way and unfortunately caught VVD awfully in the process.
Yes, he just threw his body in the way by doing a slide tackle feet first on knee height as he has done several times before. This is not only poor goal keeping it is downright dangerous one.
You said you played as GK yourself and so have I. Over 400 matches in more than 20 years on mostly pretty high amateur level and not once did I make a challenge like this. The reason for that is that I was properly trained in goal keeping and as a professional GK I would assume Pickford was aswell. Slide tackles is one of the first things you (re)learn as GK and train extensively. In the vast majority of the situations a sideways tackle where you build a wall with your upper body, arms and hands to cover as much space as possible is always the better choice but in the rare occasions when you have to resort to a frontal tackle you have to make absolutely sure to keep your feet and legs as low as possible to the ground because otherwise you won´t hit the ball first and only the opponent which will nearly always result in either a pen or a red card.
This was not some unfortunate collision where Pickford ran into a player he did not see or caught him after a proper slide, He did not slip either but jumped into a player with a motion that has a high likelihood to injure a player. That is textbook dangerous play, punished by a red card and a three game ban. Intent matters little here, unless you want to advocate for an even harder punishment.
The problem here is also that this not an isolated incident but something I have seen from Pickford at least three times now. At that point, you could definitvely argue against clumsiness or recklessness but more towards a deliberate tackling technique that should never be used by decent GK, let alone a professional one.