I have a very sad dragon fruit plant (my first, and I'm not finding ways to tell which type) that is turning purple/brown and feeling limp and am looking for resources on identifying the problem.

I am in Arizona where we have had a few freezes this winter, but not long-lasting. There has also been a lot more rain than usual. At first, I thought it was feeling overwatered from the rain, so I've been trying to restrain my urge to "do" something for it, but now I'm worried that it might be something else. I've wanted lots of sun to help dry out the extra water, but am not sure if that's causing sunburn.

Notably, I made cuttings and they are showing similar coloring, even though they've been removed from the freezes and brought inside (which has also kept them from excessive rain). They do look healthier below the soil (where roots are starting to form), so I'm not sure if this is more finding a sun/water balance.

They are all in cactus mix soil, with a small amount of cactus fertilizer.

Is this winter? Sunburn? Overwatering? Root rot? Disease? How do I tell?