I posted the stats because you questioned the results, as if 20+ games wasn't a large enough sample size of games to show the difference a goalkeeper that is even relatively average in most areas makes to us defensively. Also, there is this bizarre notion that Henderson is a poor shot stopper or that "failed" with his opportunity last season or showed that he wasn't good enough, which is ridiculous and the statistics prove that. He took his opportunity and did enough to earn the shirt for this season, which obviously didn't end up happening due to him getting Covid.
Like I said, I'm not saying I think he is good enough or that long term he's the correct choice, and if we are getting rid of him to fund a replacement for De Gea then I'm all for it. If we are getting rid of him to stick with De Gea for another season then the club is frankly insane and we should have brought in a manager who wants to defend deep and protect the goalkeeper. Personally I would have kept him and played him next season, we know he suits the defenders and the incoming managers style better than De Gea which means we can at least begin building properly and spend this years money in areas such as central midfield, full back and attack where we badly need players, before going for the gold-standard £50m+ goalkeeper (someone like Mike Maignan) next summer once we hopefully don't have some many holes in the team and are - also hopefully - back in the Champions League.
In terms of the high line, we played many games early on under RR trying to play high up the pitch but all it took was one ball over the heads of the centre halves and the opposition were in because the goalkeeper was not coming to deal with it. So I should correct myself to say we *tried* to play a high line, but realised relatively quickly that we couldn't with De Gea behind them.