I'll just point out that it is, still, a personnel issue.
Playing Djed on the left because Udogie is injured for the majority of the time, limits us down that flank. It's a personnel issue because we lack a genuinely good left-footed player to swap in for Udogie there. You can see Frank's desperation here given he threw on the aged Ben Davies to try and change things - I have no doubt it's because he's at least left footed and this can offer some width down that flank.
Vicario playing out from the back does not work - it didn't work for Ange, won't work for Frank, but it's the basis of modern tactical approaches and so we are forced to rely on Vic for that regardless. And get regularly punished for it as it's clear his technique and (particularly) decision-making, are not up to the mark.
We play Xavi in the middle even when he's having one of his anonymous games because no one else can conduct play that far forward, with Maddison and Kulusevski out. And in the middle, no one can really conduct play from deep amidst the group of midfielders we have.
If VdV goes down again, we will see further tactical issues because we have no left-footed player to replace him, nor one as speedy as he is. Both of those will impact our buildup and height of our line.
So, ultimately, we're paying for some very, very poor squad management that took place over years - none of this is the work of one man, one window, but a club approach that has seen a haphazard squad assembled over nearly half a decade.
It will take a long time to fix, and until then we'll keep seeing inconsistency. And this will be the case regardless of the manager you appoint, because they all have systems they want to play, and all of them will mean being let down by certain parts of this Frankenstein squad assembled across multiple managers and eras.
Give Frank time, money and patience. Nothing else will work, imo. I say this as someone who wasn't too convinced by our choice of Frank to begin with - but having chosen him, you have to give him time.