An update:

I tried controlling the mold with fungicide and H2O2, no use, it just kept coming back.

Over the weekend, I've cleaned it up and repotted it. Most of the roots died off, only two left. No signs or new root growth either, as I mentioned earlier, the new growth died off right after the original repot. I put some rooting compound on, and added KLN to the water as well.

The lowest leave has started turning yellow and limp. A sign that's it's not getting enough water. Hopefully, it will do better after this repot, and start growing roots again soon.

I ran into a similar issue when I repotted into s/h. Hopefully your phal grows new roots, it will eventually be okay though it'll be set back for a while. Expect smaller leaves and slow growth for a while. Keep it shaded, warm, and follow the guidelines for using KLN.

If you used a rooting powder on the plant, it is WAY too strong for orchids and will actually cause more damage.

The idea is a time repotting to coincide with the start of growth of new roots, not new growth of old roots (that's better than none, but not great, as the old part of the roots will succumb.

If you lose new roots on a phal, you're allowing it to get too cool.

No that your plant has no roots, it has no way to take up moisture, but can lose moisture through its leaves, so you need to put that clear plastic bag back over it to slow the process, and definitely want to put it on a heat mat.