How are you able to gain stakeholder alignment (or more so decisions) at the C-level if you work at a flat organization, however, there is still a lot of implied levels?
Similarly to influencing stakeholders without authority on an XFN project, there are a series of steps you can take gain stakeholder alignment at the C-Level on a decision, project, or set of approvals.
Develop a DIN framework Start by developing a DIN (Decide, Input, Notify) framework that will allow you assign roles for each stakeholder you're working with. It should be reviewed with your cross-functional peers to ensure their respective leaders are included with the right role. Typically this can be vetted by senior leaders on your team. In a "flat" org, there should be very few decision makers, and mostly folks categorized as "Input" or "Notify."
Layout the critical path to getting buy-in and decision. Next step is dependent on company culture, how input is gathered and ultimately how decisions are made. It's critical to deeply understand this process so that you're being as efficient as possible (not wasting people's time), and getting to the decision as soon as possible. How are you gathering feedback from your stakeholders? What forums are you using to provide updates to your stakeholders? Your critical path to a decision and alignment should include how you will gather input/feedback including how many rounds of feedback there will be. If the ultimate decision will be made at an exec C-level forum, there is likely a sequence of reviews that need to happen before your project even reaches this forum.
Identify peer and exec champions - You'll need supporters from other teams and an exec champion to help you drive the decision, approval, or whatever else is needed when the time comes. Supporters will likely self-identify through the review process. Your exec champion should be identified with help from your manager.
Getting C-level alignment in a relatively flat org with many stakeholders was a very common situation at YouTube. An example of this was our 2024 strategic plan for YouTube Shorts. Ultimately, our 2024 plan needed to be approved by our CMO and CEO, both designated as Decision makers. Along the way, there were MANY stakeholders we needed to gather input from and notify along the way including product, business, and global marketing partners. Establishing our DIN framework and critical path and sharing this with our respective stakeholders helped establish a clear and efficient roadmap for the planning process.