My philosophy is to only consider fertilizer when there is active growth and it comes second to water balance: root surface vs foliage surface vs temperature-light x deficit in air humidity. Like Russian dolls i don’t look into the next lower priority step if i am not satisfied with a high priority step : medium-high indirect light and water balance. N.B. Light is also a factor in water balance: the plant open stomata on the leaves to absorb CO2 under high light and doing so can dehydrate a bit more. Keep your conditions stables and the plant will adapt, wont be the most beautiful orchid but it should adapt if the roots aren’t rotting too much. I successfully kept cattleya, oncidium and phalenopsis in such conditions of years before i moved to terrariums.

I am surprised that the leaf showing a touch of yellow isn’t the bottom one.