Hi I also have a Fukien tea and have learned a lot! I know if the leaves are crispy its under watering and if they are just yellow turning an ugly broen its over watering
To address the light issue TOO LITTLE Fukien tea I was told by a bonsai artist needs to have plenty sunlight maybe 1-3 hours direct sunlight the rest of the day indirect.
As the watering don't water on schedule like that stick a chopstick in the soil for 2-3 minutes if it comes aout dry water
Hope I helped