Unfortunately maintaining the current shape and size and detailed pinching and pruning do not go with increasing trunk thickness, at least not in the short term.
Trunk thickness is a factor of either time - lots of it, OR increased top growth. On the plus size some fig species thicken trunks even when the tree is regularly trimmed. Not sure if F. microcarpa is one of those that thickens despite trimming but the F. rubiginosa we grow down here certainly is.
Another hack that some ficus growers use to increase trunk thickness a bit quicker is to run aerial roots down the trunk. As they thicken they will fuse onto the trunk and make it fatter.
Trimming and pruning: whenever the shoots get to around 6 leaves cut back to 1 or 2. Rinse and repeat as often as the tree grows which can be 4-6 times each year. Figs don't grow much in cooler months and also don't recover as fast so generally let them be in winter.
Figs love fertilizer so fertilize often. They are not fussy and will love any fertilizer you can give them. Liquid fert every 2-3 weeks while they are growing or solid fert every 4-6 weeks.
Repot in warmer weather.
Most ficus, including F. microcarpa, DO NOT like cold. Background in the photos looks like a warmer part of the world so you may be able to keep yours outdoors but if your area experiences frosts you'll need to move the tree indoors through cold weather.
Obviously what you do and when will depend on the local climate. You have not included a location in your profile which makes it real hard to be specific about when to do what for your area. You will note that most members here have added a city or region to their profile so others can understand the local climate a bit better.