[lmg643]

The main question I have, which I don't see addressed in your description: do you have a meaningful equity stake commensurate with the contributions you perceive you made?

You might need to adopt the "owner's" mentality - which is that as long as these people are growing the value of the company, you are free to focus on what you enjoy the most, while they work to make your equity more valuable.

That said - if your contributions in all these areas are truly valuable, at a small company, there's always a case to be made for someone to be spanning functional areas, if they have the expertise and chops to add value. Probably worth a conversation internally. As others have said, assert yourself a bit.