I’m not sure why you are a Category Enforced Cat B. I don’t think you exceed the 200watt category limit. However without seeing what your zFTP & zMAP are it’s difficult to tell.
Please check out the relatively new link below. It will tell you how to find your important Category power numbers.
[Possibly easiest way now is just to go into ZwiftPower and click the new My Zwift Feed link on your profile page]
You are not alone asking questions about your category. You do however have power numbers to put you into C Category so it may also be a case of finding races which suit you better than short flat races.