I think one reason why GT7's physics now lean on the understeer side is because of its broad playerbase. Not everyone would enjoy sudden oversteer the moment they turn the wheel. You can't just say "git gud" and then adjust the physics to the more expert players, which would betray the recent premise of Gran Turismo of "Driving is For Everyone". It's not a true sim.
One example was one article I have read about the 296 GT3 being forgiving in this game (understeer on turn in) as opposed to AC or iRacing with it being the opposite. In my opinion, this was done intentionally to make sure everyone enjoys the car and its recent rise to fame in real life.
On my end, I simply trail brake to get better corner entry. And just like the others said here, it's all about having the proper setup plus the driving style.