I am planning to buy the Lightburn camera, but I want to know what angle lens is most recommended for a mopa fiber laser 60W
No angle 
The more distortion that is added to the system, the more computation is required. The best thing is to have a camera mounted as high as possible directly above the workspace. The narrower the viewing angle, the better. Wide angle will add distortion again. In case of a MOPA, I’d mount it close to the head.
You don’t need any special camera, every webcam will do. So before buying, you can just grab a few and test. Once you are satisfied, you can either go on using them or buy a LB camera with similar specs as the ones you tested.
I created a video where I used a Sculpfun camera with a Monport MOPA:
It’s in German, but you can just scroll to the beginning where I showed how/where the camera is mounted.
The camera selection wizard in LightBurn can help you here - If you know what lens is your longest (requires the most offset from the laser bed) you can determine the minimum mounting height from that, then plug in the X and Y lengths of the work area of that lens.