Great thread full of interesting and well articulated points. I've plenty of vague trails of thought bouncing around my head, but not sure I can contribute much that hasn't already been covered.
The only thing I'd add, is that our senior and highest paid players need to start pulling their weight / rediscover their motivation.
Look at our best performing players this season: Ramsdale, Lerma, Rico, Stacey. Mepham done well in the last couple of games. They're all newer arrivals, on the younger side, and even the older Lerma/Rico are less experienced in PL football.
They aren't supposed to be the bedrock of our performances. They're supposed to supplement the pre existing senior players who should be leading the squad.
Aside from the usually excellent Steve Cook, and limited but trusty Gosling, all our other senior players are below par. Catastrophically so in Wilson and Fraser's case. But even Ake was making uncharacteristic errors, King not quite as clinical as usual. Franno is only getting slower. Daniels, Surman, Smith and Stanislas we haven't really seen much through injury (perhaps not their fault).
The core and leadership of the squad is missing or underperforming, so we're lumping a lot of pressure of young and/or inexperienced players.
Time for some senior figures in the squad to step up and take on the pressure.