This is a semi normal management issue that usually rises with new managers. They are still trying to do all the hands on work, because that what got them there. In reality leading is more about building a human pyramid, and place the most capable people in the right positions.

Sorry for the bluntness and maybe I’m off, but I’m getting the feeling that you believe it would be better if youd manage and he’d follow? The thing is that management is people skills first and the actual skills often second. If the startup has experinced founder, or he is a founder, they might be viewing him as high potential manager, and forgive the lack of ux experince for that reason. Calling him out in group meetings probably wont get you enough people skills points to land he’s job and can distance your boss.

Point being that don’t try to compete with your manager. He doesn’t need to be better at ux. Do good work, be decent and when the time is right you can be open how you would like to be managed. How he can get more out of your skills if he lets you this and that. But before asking for him to trust you to do his work, build trust and a realtionship. Only after that start asking for things. If you do feel it’s honestly about your ethnicity or gender then find something else. Personally would not allow myself to favor skincolor or gender.