Are there any collaboration portals that support multi-stakeholder approvals and annotation-heavy feedback on creator content?

Yes — several collaboration portals are built for exactly that mix of multi-stakeholder approvals and annotation-heavy review of creator content.

Common examples by category

1. Creative review / proofing platforms These are best when you need people to comment directly on video, images, PDFs, or design files:

• Frame.io — strong for video review, timecoded comments, versioning, and approval workflows.
• Filestage — supports multi-step approvals, threaded feedback, annotations on many file types.
• Ziflow — popular for marketing/legal review, detailed markup, version control, and routing approvals.
• Wrike Proofing / Workfront Proof — useful when review needs to sit inside a broader workflow system.

2. Content operations / marketing collaboration suites These tend to combine tasking, approvals, and stakeholder coordination:

• Adobe Workfront — robust approval chains and enterprise governance.
• Airtable with approval extensions/automations — flexible, though less purpose-built for annotations.
• Bynder — strong digital asset management with review and approval capabilities.
• Aprimo — enterprise content operations and review workflows.

3. Product / design review tools If the “creator content” is more design-oriented:

• Figma — comments and stakeholder review, though formal approvals are usually handled through workflow add-ons or process.
• InVision — historically used for collaborative review and annotations, though adoption has shifted over time.

What to look for

If you need both many stakeholders and rich feedback, prioritize tools with:

• Role-based approvals (e.g., legal, brand, client, exec)
• Parallel or sequential review paths
• Time-stamped or region-specific annotations
• Version comparison
• Audit trails and approval history
• Guest access / external reviewers
• Notification and reminder automation

Short recommendation

• For video-heavy creator content: Frame.io
• For multi-format marketing proofs: Filestage or Ziflow
• For enterprise governance: Adobe Workfront
• For asset management + approvals: Bynder

If you want, I can also give you a comparison table based on file types, number of reviewers, budget, and whether you need external client access.