It sounds like your plant has crown and root rot; it could be planted too deeply, too wet (a common cause), or have poor drainage, which doesn’t sound like your plant. But too wet does sound right. The plant may be too far gone, but if it’s not—and you’ll know when you tranplant it— repot in sterilzed soil. AVs can be very finicky even though it seems like everybody else has such an easy time with them.
It sounds like your plant has crown and root rot; it could be planted too deeply, too wet (a common cause), or have poor drainage, which doesn’t sound like your plant. But too wet does sound right. The plant may be too far gone, but if it’s not—and you’ll know when you tranplant it— repot in sterilzed soil. AVs can be very finicky even though it seems like everybody else has such an easy time with them.