Black spot on zns. Roqueburne

[Pieceittogether]

Ok they started 6 month ago and now they are all over and all the leaves have similar patterns now. There no pests and root are in good condition. I looked for similar pattern; the answer was either fungus or normal on this type. I treated it with physan 20, but that was no point based on some of the literature of this needing something systematic vs outside. So my question I have no problem destroying it, however I see new growth and wonder if I should save it, but first I don’t know what is it a bacteria or a fungus or virus(harder to diagnose). Also how contagious this is I already I isolated it. What treatment route should i proceed with. This orchid get medium light, with RO water with Peter excel ca mg 15-5-15 1/4 tsp weekly. The medium is the original that came with from kalpantropicals. Thank u in advance for guidance