How screwed is my rhaphidophora tetrasperma?

I bought this plant rooted in bark and sphagnum moss about a month ago, and transplanted it into soil + perlite. Two weeks ago (first picture) it started developing these yellow spots with brown, patterned centers. I cut them out / off with a sterilized knife and sprayed the whole thing with fungicide. Today (remaining pictures) the remaining leaves are largely fine, but I’ve noticed similar spots on some petioles, and purely brown spots on the main stem.

If this is a fungus, is it rotting from the inside out or outside in, and can it be treated? If it’s a virus or something else, what are my options? Any insights would be greatly appreciated!