@Zhiming_Liu Thanks for the reply!
For point no. 1, do you mean to say .pt to .onnx, as ultralytics provide that option. As ultralytics provide that option of converting .pt to .onnx, to best of my knowledge, .pb to .onnx is not provided in its API, and if it is so can you please share the link to the resource mentioning the same.
I appreciate your quick and prompt response. Thanks!