What species do you have there? And is it just indoors for the picture, or does it live inside (In which case I wonder why there are no leaves on the tree).
In the end, you will need to decide what you aim for with this tree. I see a lot of curves in the trunk. As such, I would expect very dynamic branches too. Unfortunately, the previous owner did not follow-up and missed wiring the branches out. So I would consider wiring branches that are still pliable and trimming a lot of branches back to remove the straight sections. The trimming back of course can be done over multiple seasons to keep a pleasing looking outline for the time being. (I would not have the patience, and would do all that work before growth picks up again. But I have a yard full of trees so having long-term ugliness in some trees is no issue for me!).
Next to that..
@HorseloverFat already hinted at more extreme steps, which certainly for people new (?) to bonsai are often too drastic. The shape of the trunk is a bit extreme. I could imagine this long-term ending up into 2 trees by layering off the top 2/3 and using the first branches at the leftover base to grow another tree. But that is not the first thing if you just got this.