I also question an impending FEE. I do believe the current exhaust is not helping matters... possibly contributing more to rear tire issues than aiding in downforce but it's specualtive.
I think there's some clues to be had in the continued use of that front wing. In my mind, the front wing- being catilivered forward of the front tires, adds front downforce BUT ALSO "reduces" rear downforce via the cantilever effect. The fact that new front wings (presumably higher down force) upset balance, I believe is a result of this dynamic... which is exaserbated by the short wheel base effectively increasing the levered effect at the rear. This is possibly why they haven't done much with the front wing (including a full flex design) as their problem is at the back and more down force up front upsets that.
I confess that I don't know the sporting regs in this regard but it seems to me that shifting the rear wing planes further back, could help in this regard. A longer wheel base would also but that's not really doable at this point. It seems the rear wing endplates extend well aft of the foils... why couldn't the foils be shifted aft to add a greater rear cantilever effect so that rear downforce would be less effected by the front forces? Perhaps front and rear downforce could be improved without adding drag?
As for mechanical traction as required in Monaco- I'm not sure what can be one there.