I did some open lobby practice yesterday as well. It really surprised me how much speed the GTEs can take into a corner. They need to brake a little earlier, but I guess their entry speed into a corner is not significantly lower than the DPs.
Lapping was quite okay. Busstop, as you already said, better take it easy and tend to back off instead of going side-by-side. Next tricky corners imo are nr. 4 and 5:
Approaching turn 4, the DP has quite some overspeed and if a slower class car is in front, you can only pray that keeps sticking to the racing line and moves to the left coming onto turn 5. Imo the only way to lap fast (and safely) is to dive on the inside. Braking becomes absolutely crucial then because it's easy to miss the braking point or to hit the grass on the right. It felt like I had to pass a GTE or GT3 there every single lap. So, better practice it over and over again