So, Poppy hasn't received any buffs in a long time, as in, I don't even remember the last time she had a positive change in the patch notes. I know she appears really strong but that is just a byproduct of lane bullies being nonexistent in the toplane. You also can't play a ranged carries toplane (Poppy counter) anymore because teams need a tank, and carry junglers can snowball and build off-tank so there is literally no reason to go tank in the jungle (Its not unviable but its un-optimal and nobody in soloq wants to play a sub-optimal role) Add to that that melee (tank) supports are currently in a bad place and tops are forced to play tanks or get flamed.
If tank junglers got buffed
If Melee Supports got buffed
If Lane-bullies got buffed
you wouldn't see poppy. Poppy hasn't been buffed and isn't an outlier, the game has changed around her, and nerfing her isnt going to improve overall balance