Hard Shift to Drive - Parking on Hill and Slow Acceleration Sometimes

Have a 2006 Honda Civic EX automatic. 2 Qs.

When shifting from P to R on a hill, I get a loud boom sound. Is this normal or am I not following correct parking procedures?

I also notice it takes me longer to accelerate on a freeway on-ramp after a complete stop. I am driving at 25mph and I try to gently accelerated, but no mph increase. My mph increase if I really step on it and the rpm is 2.5 to 3. Is there something wrong?

When parking, you will need to firmly set the parking brake before releasing the brake pedal.

You will most likely need more than 2.5-3k rpms for proper acceleration.