We have a similar situation in our co-op, confirmed, the sponsor is also the managing agent. We have begun the process of looking for a new managing agent - It is not an easy execution, but the hunt is on.
Why --- Upon my joining the board, I was ready for change, and had experience in finance to see some of the blatant conflicts of interest.
As we progressed to hiring an engineer for a physical survey, moved onto new fuel suppliers, it was becoming clear the sponsor who objected every step of the way, was now using the managing agent to slow things down. An example - the check can’t be signed because nobody is in today or my favorite, we can’t tell you who is in arrears today because you need to wait until the third Friday of the month for the financial reporting pack.
The managing agent was slowing us down. We have not confirmed our new managing agent, but we are actively exploring. Getting new contractors, etc has largely fallen to us as resident purchasing shareholder board members to procure and meet with contractors for each project.
I would document things that seem strange, ask questions in writing, know and understand your prop lease, by laws, and house rules and begin to form the necessary coalition to begin the push for reasonable change.
A side note - It won’t be simple or easy, but keep everyone in the loop, form a coalition, set clear objectives and keep the focus on the true intent for your co-op's existence - to provide a permanent residence for purchasing shareholders - our prop lease even --- states as a first class residence.
Keep it civil, document document and document, patience and preservation will go a long way to improving the situation.