Currently, using DWGStyler to rotate text and output to DWG, you will find that the angle of the text is not changed in the output DWG. But if you use FME Data Inspector to view the text before the output, you will find that the text has been rotated. I tried a lot of methods, including using Rotator, setting autocad_rotation, autocad_text_rotation, but all got the same result.

Finally, the comment of mark2catsafe in the following QA was inspired. I gave autocad_original_rotation the value of autocad_rotation output from the Rotator, and finally got the desired result.

How to define the rotation angle of annotation? (SHP to CAD)

If the user have to set autocad_original_rotation to be able to change the angle of the output DWG's text, it will be confusing to the user. Because it is a property unique to the DWG format, I think that the setting of autocad_original_rotation should be implemented inside DWGStyler or inside the DWG Writer, rather than having the user manually set it.