Brake booster is bad still requires more than typical pressure to stop the vehicle

Hello,

When you have a stiff brake pedal and it requires more than usual force, it typically means there is an issue with the vacuum assist for the brake system. As you know the brake booster provides that assist.

Frist check the vacuum hose connected to the booster. Make sure it is secured and there is not restriction on that hose or cracks.
The brakes will require more effort due to a vacuum leak on the hose to the brake booster.

https://youtu.be/4ktw1X4W_-k

I have attached diagrams for your reference.

Please let me know of any questions.
Thank you.