Acceleration Issue plus A/C, could they be related?

I have a 2016 Q50 2.0T Premium that I do not plan to keep. It was in great working condition until first the a/c went out. Weird thing is, every time I have to turn on the road, the a/c starts to work again, or even if I’m going up hill or down hill. It used to work at night, so I thought it was because of the heat from the sun. But recently, it would work for a little bit then it would start blowing hot air again.

As for the Acceleration issue, my car drives up to 60 and sometimes 80 mph. But not too long after, the car would make a weird slow and deep vrooooooooom sound when I try to accelerate. Instead of accelerating, the car decelerates significantly. Just yesterday while I was driving my car, it went from 70 to 60 from 60 to just under 40. I was about 37 mph in a 75 mph highway. Even switching modes from standard to sport doesn’t work.