Pls check my understanding of red/blueshift

I’m hoping you can check my understanding of red/blueshift and maybe clarify a couple of things I’m having trouble understanding.

Is it correct that redshift occurs when the wave length is stretched out and the frequency decreases? Amplitude should stay the same though right?

There are two ways redshift can happen. The distance between the energy source and the observer is increasing and/or energy loss. Because EM waves need to move at a constant speed (in a vacume) the only way to shed energy is decrease frequency causing wave lengthening?

When red/blueshift occurs due to distance increasing/decreasing between the source and the observer does the lengthening and contracting of wave lengths have anything to do with space dilation?