Ap assassins are weak IMO right now

Last 5 Leblanc games in ranked I've had at least 14+ kills in each, but it feels like if a ad bruiser builds maw and steraks, he can do just as much damage as me in a team fight and stay alive much longer. Lets take a look at a game I just played about two hours ago. On LB my job is to delete the adc, and in this game we were vs kog. Every single team fight I was able to delete him even with his Morgana shield from the support. It didn't matter, even when I somehow killed him and Morgana simultaneously, then backed(because I was low) my team lost the 4v3. The enemy was garen, devoured shyvana jungle and ekko(btw, even tho I solo killed this ekko, i see now that gold and play players just stand in the middle of his ultimate every single fight and never learn their lesson), anyway, my lee, trist, gnar, and blitz were unable to win the 4v3 and it wasn't even close. And even in the fights where i would stay after deleting kog, I had to burn through the ad bruisers shields and Ekkos ultimate.

I love playing lb and assassins but I'm seriously starting to think a change is needed to carry more. Been thinking a tankier diana(kinda like how tank alkali is except you have better split pushing ability), am I the only one who feels ap assays are super weak right now?