They grow best outside until just before a frost if you can.. That way these issues will only happen from Nov-April and not year round
It can grow somewhat naturally with proper sun, rain and so on.
Bringing it back and replacing would be pointless only because the new one would most likely do the exact same. When indoors watering is much different then if it were outside. A lot less because there is no sun to dry out the pot.
I hope it turns around for you it's a nice size.