Jump_912 wrote:
watering method - tray with around 1 inch standing water
last plant location - indoor, in front of window with shaded sunlight
the previous plant location was outdoor on a shaded location but will occasionally getting few hours direct sunlight.
This sounds like your problem. Flytraps need between half a day and all day
direct sunlight. Being light deprived and very moist-wet all the time will kill it - although since your rhizome is not rotted, your moisture level may have been correct. Put it back in sphagnum moss about 2 cm below the surface (make sure you orient the roots downward) and give it as much direct light as you possibly can. You don't want the sun directly hitting the rhizome because it will burn it but the direct sun will help keep the moss breathing and will ensure that when the rhizome
does send up a new shoot, it gets enough light to grow and recharge your plant. Give it as much water as is required to keep the moss around the rhizome moist. Not too wet but never allow it to fully dry out. It you can manage that, it should start to grow back within a month.
Once it's healthy again, months down the road, you'll need to reconsider dormancy which requires cold temperatures so you will probably need to do a fridge dormancy. But for now just focus on getting it growing again!