No fertilizer until you are sure it is fully recovered. It can't use fertilizer right now.
Now the story is clearer. I should have picked up on the feeder roots being mushy, with only leader roots remaining. My oversight.
Too much water means that the potting media remained soggy, not simply moist. In that case, keep the potting soil a little on the dry side but you still want it slightly moist. You might want to lightly water it if you did not do so when you re-potted it and then wait perhaps seven days. Then stick a finger deep into the soil and see if it remains moist. Without those feeder roots, the plant cannot take up much moisture. Be sure not to leave water in the cache saucer after watering. Dump that water out.
All of us tend to overwater our houseplants thinking "more is better". I deal mainly in orchids and I would guess that 90% of all the orchids killed are killed by drowning, aka overwatering.