Vanda fungus issue

[drosera]

Good afternoon, I have a serious problem with some of my Vandas. They have been attacked by some fungus (they look like Cercosporoids or something similar), with black spots and dots, some of which become necrotic. In addition, the leaves have a very dark colour (but the roots seem to be in good condition). I have treated them with Banrot a couple of times, but they do not seem to improve. I grow them under LED lights, in an environment with high humidity (70-90) and temperatures of 15-16 ºC at night and 22 ºC during the day. In summer they go outside. The photo corresponds to Vanda Roberts Delight Black. I would really appreciate some help because I don't know what I can do. Thank you very much!!!