I know camber is bugged and useless, but is toe also useless? Or just in this particular case?
Toe works just fine, but if you add camber, you add turn-in stability and mid-corner understeer. And then you need to add increasing amounts of -ve toe to compensate for this extra mid-corner understeer. The more -ve toe you add, the slower the turn-in becomes.... This is an ever increasing circle of understeer (the killer of lap times).
Once you remove the camber, you can remove the toe, which gives your car more entry rotation with at least as much mid corner grip. If the car had good mid and exit front grip, but is too sharp on turn in, you add a tiny a amount of LSD decel.
All settings are something of a compromise, but there are some combinations that work against each other, and some that have a more specific effect.
Personally, I prefer to use ride height rake (usually a higher front than rear) as the primary balance adjuster, focusing on minimising mid and exit understeer, and then fine tune any
excessive enrty rotation with tiny amounts of LSD decel (small LSD changes have a massive effect in GT6). With toe, you're always compromised for either entry or mid, or exit corner rotation.
It's always something of a balancing act between entry, mid and exit grip, but camber is almost always destructive.