Ask the champion why the stakeholder's involvement is needed and what would make a discussion valuable. They may be busy, delegate the topic or not see a current problem. More pressure may not change that.
Offer a focused question, short decision brief, technical answer or relevant reference. Make the request smaller and tied to the person's responsibilities rather than demanding a full demo.
A confirmed peer or colleague connection can provide context or an appropriate introduction. Coordinate with the account owner and champion. Do not imply an endorsement or personal relationship that does not exist.
A stakeholder can decline. Record what was learned, adjust the account plan and revisit only when circumstances or relevance change. A lack of access is not proof that a hidden route must exist.
Orbb can help research people and possible paths. Its role is improving the evidence and execution behind a suitable approach, not guaranteeing access to someone who does not want the conversation.