Dropping an AP class senior year

No

Have you applied anywhere ? If so, you’ll have to make them aware. If not, you have enough rigor so nothing to inform.

Will they know you dropped it ? Yes.

But keep and get a C/D - they’ll know too.

Make sure you have enough classes to graduate and have at least 3 lab sciences.

5 APs is many.

Will it hurt in admissions ? Maybe but it might hurt staying in too.

If you get rejected to a school, you’ll never know why. It may or may not be because of this.

Good luck.