What would be the benefits of implementing this full nested control architecture for the control compared to my current implementation
Textbooks are always a great source of information!
Reference: "Feedback Systems - An Introduction for Scientists and Engineers", Karl Johan Astrom, Richard M. Murray.
Could a simple if condition on a specific ...
For every component you can search for data sheets over the respective manufacturer site. You can know the rated current of motor otherwise on the shopping site. Then find a motor driver for that rating. Or else you can design it on your own.