So the thing with VFTs is that they actually require dormancy during winter, which may be the reason it’s not looking too great if it’s kept in a growing state when it’s meant to be dormant. They also need nutrient poor soil like peat moss (no fertilizer) and water that’s low in minerals.
The jar looks great with or without the VFT, but if you’re looking for a carnivorous plant that doesn’t need dormancy I highly recommend cape sundews. Pretty much all carnivores require soil and water that’s low in nutrients/minerals, but cape sundews and similar species are a lot less finicky than others