Keep your Fiddle-leafed Fig in a sunnier location. It does best in direct sunlight. Yours appears to be stretching a bit due to the reduced light it has had. Improving the light is the best thing you can do for it.
Your plant is pretty hard to over water. You should completely saturate the soil as soon as the surface of the soil is almost dry to the touch. (Do not rely on a moisture meter becomes they are notoriously inaccurate.) Never give it a little water - always water enough so that some trickles through the drain holes.
You can prune off the top to any height. You will probably just get one new leaf growing in just below the pruning cut. Occasionally a second leaf will emerge at the same location. It is not likely to produce new branches for you.
The pot it is in is fine, at least for now. When it reaches the point where you have to water it thoroughly more than twice per week, then it may be ready for a pot one size larger. The exposed upper roots are fine. They have developed a bark covering that would actually be damaged if they were now covered with damp soil.
There is no evidence of any pests or diseases.
It will contiure to occasionally lose a lower older leaf as it adds new leaves on top.
